GiD 10 Reference Manual Pre and post processing system for Numerical Simulations.
International Center For
Numerical Methods In Engineering (CIMNE)
INTRODUCTION
INTRODUCTION
GiD is an interactive graphical user interface used for the definition, preparation and visualization of all the data related to a numerical simulation. This data includes the definition of the geometry, materials, conditions, solution information and other parameters. The program can generate a mesh for finite element, finite volume or finite difference analysis and write the information for a numerical simulation program in its desired format. It is also possible to run these numerical simulations from within GiD and then visualize the results of the analysis.
GiD can be customized and configured by users so that the data required for their own solver modules may be generated. These solver modules may then be included within the GiD software system....
This manual has been split into five clearly differentiated parts.
The first part, General aspects, provides information on the basic aspects of the program. In this way, you can gain confidence and become more familiar with the system in order to take advantage of all the available facilities.
The second part, Preprocessing, describes the preprocessing functionality. You will learn how to configure a project and define all its components - geometry, data and mesh.
GiD is a geometrical system in the sense that, having defined the geometry, all the attributes and conditions (i.e. material assignments, loading, conditions, etc.) are applied to the geometry without any reference to a mesh. Only when everything has been defined is the meshing of the geometrical domain carried out. This methodology facilitates alterations to the geometry while maintaining the definitions of the attributes and conditions. Alterations to the attributes or conditions can be made simultaneously without needing to reassign the geometry. New meshes can also be generated if necessary and all the information will automatically be assigned correctly....
When installing GiD on Windows, the useful way is to start GiD from desktop icon:
There is also added a direct access from the programs list of the start menu.
An special option is to start 'GiD safe mode', then a window will be open to ask the user to select how to handle OpenGL graphics: by software or by hardware (some graphic cards and drivers have problems with the hardware option, the screen can show corrupted images or even GiD can crash)...
The user interface allows you to interact with the program. It is composed of buttons, windows, icons, menus, text entries and the graphical output of certain information. You can configure the interface to display things in a certain way, and may use as many menus and windows as required.
The initial layout of GiD is consists of a large graphical area with pull-down menus at the top, a command line at the bottom, a message window above it and an icon bar. The project that is being run is displayed in the window title bar. The pull-down and 'click on' menus are used to access GiD commands quickly. Some of them offer a shortcut for easier access - these are activated by holding the ...
As well as selecting the functions to be used, the left mouse button is used to select entities, either individually or picking several within a given area (see Entity selection), and to enter points in the plane z=0 (see Point definition).
The middle mouse button is equivalent to escape (see Escape).
The right mouse button opens an on-screen menu with some visualization options. To select one of them, use the left or right mouse button; to quit, left-click anywhere outside the menu....
All commands may be entered via the command line (found at the bottom of the GiD window) by typing the full name or only part of it (long enough to avoid confusion with other commands); commands are not case-sensitive. Any function from the Right buttons menu can be used by typing all or part of its name in the command line. Special commands are also available for viewing (zoom, rotation and so on) and these can be typed or used at any time when working from within another function. A list of these special commands is given in View (see VIEW).
Commands entered by typing are word oriented. This means that the same operation is achieved if one writes the entire command and then presses enter or if one writes a part of it, presses enter and then writes the rest....
The following features are essential to the effective use of the GiD system. They are, therefore, described apart from the preprocessing facilities section.
Many functions inside GiD need points to be defined by the user. Points are the lowest level of geometrical entity and therefore the most commonly used. Consequently, it is important that you have a thorough understanding of how to do this. Sometimes an existing point is required and sometimes a new point must be defined.
All the options explained in this section are available through the window shown above (see Coordinates window...
Points are picked in the graphical window in the plane z=0 according to the coordinates viewed in the window. Depending on the activated preferences (see Preferences), if you select a region located in the vicinity of an existing point, GiD asks whether it should create a new point or use the existing one.
GiD offers a window for entering points in order to create geometries easily, defining fixed or relative coordinates as well as different reference systems - cartesian, cylindrical or spherical.
The coordinates of a point can be entered either in the enter points window or in the command line by following one of two possible formats:
Local coordinates are always considered relative to the last point that was used, created or selected. The Utilities -> Id command allows you to make a reference to one point (see Id
). Then, to define points using local coordinates referring to the same point, use Options and Fixed Relative when entering each point. The last point selected or created before using this will be the origin of the local coordinate system. It is also possible to enter this central point by its coordinates.
The following are valid examples of defining points using local coordinates:...
If the Base button is selected (it is set by default to No Base), a point can be retrieved from any of the other modes. Then, the coordinates of this point, instead of being used immediately, are written in the command line and can be edited before they are confirmed.
It is possible to change the way that GiD works with points by default via preferences (see Preferences).
When using a function that asks for a point, e.g. line creation, GiD will expect you either to enter a new point (the cursor is a cross) or select an existing one (the cursor is a box). To change from the first mode to the second, click the Join button in the Right buttons menu or the Contextual mouse menu, or use the shortcut (Ctrl-a); the option will then change to No Join. Simply select an existing point to pick it. (Ctrl-a) switches from Join to No Join and vice versa.
The special options FJoin and FNoJoin force GiD to change either to Join mode or No Join mode independently of the previous mode....
With this option selected, when creating a new point or line, etc., you can only select points that lie on existing lines. To switch it off, simply select No Point in line.
With this option selected, when creating a new point or line, etc., you can only select points that lie on existing surfaces. To switch it off, simply select No Point in surface.
Using this option, you can pick over a line in the graphical window. A vector will be returned that is the tangent to the line at the point you have picked.
Using this option, you can pick over a surface in the graphical window. A vector will be returned that is the normal to the surface at the point you have picked.
It is possible to use an auxiliary grid of lines to define 2D points easily. The 'snap' function can be activated to force points to grid intersections.
From the preferences window (see Preferences) it is possible to set the separation between lines and to show the origin, extents, etc. of the coordinates.
There is a small button in the bottom right-hand corner that activates or deactivates the grid and 'snap' functions....
Many commands need to be supplied with entities before they can be applied and the method of selection is always the same. Before selecting entities, you are prompted to decide whether to select points, lines, surfaces or volumes (in some cases this decision is obvious or it is made within the context of the option).
Within one of the generic groups (points, lines, surfaces, volumes, nodes or elements) it does not matter what type of entity is selected (for example, an arc or a spline, both line entities are selected in the same way). After this, if one entity of the desired group is selected, it is colored red to indicate it has been selected and you are prompted to enter more entities. If you select away from any entity, a dynamic box is opened that can be defined by picking again in another place. All entities that are either totally or partly within this box are selected. Once again, you are then prompted to enter more entities. ...
The escape command is used for moving up a level within the Right buttons menus, for finishing most commands, or for finishing selections and other utilities. This command can be applied by:
pressing the middle mouse button;
pressing the ESC key;
pressing the escape button in the Right buttons menu;
GiD includes the usual ways of saving and reading saved information (Save, Read) as well as other operations, such as importing external files, saving in other formats and so on.
With this command, GiD allows you to save the current project with another name.
When it is selected, an auxiliary window appears with all the existing projects and directories to facilitate the introduction of the project's new name and directory.
With this option it is possible to read a file in DXF format (AutoCAD 2002 version).
GiD is able to read most of the entities, which are: POINT, LINE, ARC, CIRCLE, ELLIPSE, SPLINE, LWPOLYLINE, MLINE, POLYLINE, VERTEX, TRACE, SOLID, 3DFACE, 3DSOLID, BLOCK, INSERT
A very important parameter to consider is how the points must be joined. This means that points that are close to each other must be converted to a single point. This is done by defining the variable ImportTolerance (see ...
With this option it is possible to read a file in the Parasolid format (version 14000 - ASCII or binary).
The most usual Parasolid file extension is .x_t for ASCII and .x_b for binary format.
The variable ImportTolerance (see Preferences
) controls the creation of new points when a Parasolid file is read. Points are therefore defined as unique if they lie further away than this tolerance distance from another already defined point. Curves are considered identical if they have the same points at their extremes and the "mean proportional distance" between them is smaller than the tolerance. Surfaces can also be collapsed. ...
With this option it is possible to read a file in ACIS format (version 7.0). GiD reads the ASCII version with the SAT Save File Format. ACIS files (in ASCII) have the .sat extension.
With this option it is possible to read a file in VDA 2.0 format.
A very important parameter to consider is how the points must be joined. This means that points that are close to each other must be converted to a single point. This is done by defining the variable ImportTolerance (see Preferences
). Points closer together than ImportTolerance will be considered as a single point. Straight lines that share both points are also converted to a single line.
With this option it is possible to read a set of geometric points. This format is ASCII and consists the coordinates of the points separated with spaces.
Note: If only 2 coordinates are specified, z=0 is assumed.
If 'Automatic collapse after import' was set, after the import near points will be joined, The variable ImportTolerance (see Preferences) controls the joining distance.
With this option it is possible to read a .cgns mesh with CGNS binary format. CGNS is an standard format, specialized for the storage and retrieval of CFD (computational fluid dynamics) data.
With this option it is possible to read a GiD ASCII mesh (saved with Export GiD Mesh) in order to visualize it within GiD.
It is also possible to read a new mesh and add it to the existing one. In this case, you are prompted to keep the former one or join it to the new mesh.
The format of the file describing the mesh must have the following structure:
With this option a mesh can be read from a file in GiD or STL format (see GiD mesh). Elements of this mesh must be triangles or quadrilaterals. This mesh is converted by GiD into a set of surfaces, points and lines. The geometric definition of surfaces is the mesh itself, but GiD treats them as truly geometric entities. For example, these surfaces can be used as the boundary of a volume, and a new mesh can be generated over them.
You are asked for the value of an angle. An angle between elements bigger than this value is considered to be an edge, and lines are inserted over them. As a consequence, a set of boundary and interior lines are created and attached to the surfaces to mark their edges....
GiD can import a mesh from a file with VTK structured data point format (http://www.vtk.org/pdf/file-formats.pdf). This format represent a scalar field over a rectilinear 3D grid.
In the "VTK voxels read" dialog box we can specify the isosurface value for the boundary of the body we want to extract from the volume. Besides we can choose among 3 different methods:...
With this option it is possible to read a set of mesh nodes. This format is ASCII and consists in the coordinates of the nodes separated by spaces.
Note: If only 2 coordinates are specified, z=0 is assumed.
If 'Automatic collapse after import' was set, after the import near points will be joined, The variable ImportTolerance (see Preferences) controls the joining distance.
Sometimes, you may wish to organise a number of commands into a group outside GiD, ready to be implemented in one go. To do so, commands can be written in a file and GiD will read this file and execute the commands. These commands are the same ones as are used in GiD when entered in the command line or using the commands in the Right buttons menu.
Example: Many points have been digitalized and their coordinates saved in a file. These points are to be joined with straight lines to create the outline of the geometry. To do so, the file would look similar to this:...
GiD can export the geometry in IGES format (version 5.3).
If the preference 'IGES:B-Rep output style' is set (see Preferences
), then the output file is written in Boundary representation solid model style; otherwise the surfaces are written as separated trimmed surfaces, without topological information, and the volumes are ignored.
GiD can export the geometry in DXF format (AutoCAD 2002 version). Points and curves are correctly exported, but a surface must be converted into a mesh of triangles, because DXF does not support Trimmed NURBS Surfaces.
With this option a file is written containing all the information within the project. It is created in a way that is easily understood when read with an editor. This is useful for checking the information.
Note:
This ASCII format is only used to check information. It cannot be read again by GiD. To write ASCII files that can be read again use the option SaveAsciiProj (see ASCII project
).
This option saves a project in the same way as regular Save (see Save
) but files are written in ASCII. It may be useful for copying projects between incompatible machines. GiD also allows this information to be written in a file (see Text data report
).
Projects saved in this way may be read with the same open command (see Open
).
With this option, only the geometrical entities with their layers set to ON will be saved in a new project (see Layers).
Note: Lower entities necessary to define the saved entities will be also saved in the new project (e.g. the two extreme points of a line are also saved if the line is saved).
If GiD runs the solver module automatically, this command is not necessary. However, it is useful if the solver program has to be run outside GiD, or to check the data input prior to any calculations.
This command writes the data file needed by the solver module.
The format of this file must be defined in a Template File (see Template File from Customization Manual). GiD uses the template file of the current Problem Type...
This command does the same thing as Export -> Calculation file (see Calculation file), but it uses a .bas file provided by the user, instead of using the template file of the current problem type. This means it is not necessary to select a problem type in order to run this command.
When choosing 'Others...' from the submenu, GiD asks for a .bas file (see Template File from Customization Manual) and, using that file, writes the data file needed by the solver module. There are some .bas codes available in the submenu which write output files in some formats (DXF, NASTRAN, STL, VRML). These example .bas files are located in the Templates directory of the main GiD directory. It is possible to add other .bas files to that directory so they appear in the submenu....
This option asks you for a file name and saves an image in the required format. The properties of the image (resolution, size, etc.) can be assigned in Page/image setup (see ...
This is the window where some print properties (page size, borders, etc.) and image properties (image resolution and Auto crop image option) can be set up. These settings are applied when sending an image to a printer (see Print), or to a file (see Print to file).
Note: it's possible to create images with more resolution as the screen, e.g. interesting in order to print a poster....
You can quickly gain access to files opened recently with GiD.
Recent Post Files: a list of the most recents files read in PostProcess is shown, so the user can selecet them quickier. The number of files can be adjusted here General.
Recent Projects: a list of the most recent GiD projects are shown. The number of projects can be adjusted here General...
Visualization commands change the way information is displayed in the graphical window. They have no effect on the definition of the geometry or any other data.
Generally, they can be used within any other command without leaving it. When the visualization process finishes, the first command continues.
They can all be accessed from the View pull-down menu, and most of them also by clicking the right mouse button.
With this option you can rotate the image as if using a trackball device. This means that when you left-click on a point and move the mouse, the geometric point tries to follow the mouse pointer. This can be imagined as a ball over the graphical window which is moved with the mouse.
The left mouse button can be pressed several times to engage and disengage the movement. To cancel this function, use escape (see Escape).
This option allows a dynamic rotation about the screen axes. Screen axes are defined as:
X-axis: The horizontal axis.
Y-axis: The vertical axis.
Z-axis: The axis at a right angle to the screen.
When entering this command, Z-axis is set by default and moving the mouse to the left or to the right will rotate the geometry around this axis. Clicking the left mouse button changes the axis. To cancel this function, use escape (see Escape...
This option allows a dynamic rotation of the object about its own axes. These are displayed in the bottom left-hand corner of the screen.
When entering this command, Z-axis is set by default and moving the mouse to the left or to the right will rotate the geometry around this axis. Clicking the left mouse button changes the axes. To cancel this function, use escape (see Escape).
Can be changed the axis about which the image in rotated by entering the letters x, y or z in the command line....
The default center of rotation is defined as a point approximately in the center of the geometry.
If you wish to change this center point, use this command to enter a point (see Point definition
). This new centre of rotation will be maintained until the next zoom frame (see Zoom
).
In the Contextual
mouse menu (the menu which appears when you right-click over the graphical window) the option 'Automatic rotation center' / 'No automatic rotation center' is listed. If this option is active, for each 'Zoom In' / 'Zoom Out' / 'Pan' the point of the geometry or mesh nearest to the center of the screen will be selected as the center of rotation for subsequent rotations. This variable is also present in the ...
This option changes the view to the original one, i.e. with the screen at a right angle to the Z-axis and with the X-axis lying horizontally and pointing to the right.
This option changes the view to isometric one, i.e. with the screen at the viewing direction that the angles between the projection of the x, y, and z axes are all the same.
By default, a model is viewed inside GiD using an orthogonal projection.
With this option it is possible to change to a perspective projection. In this mode, you can choose a distortion factor for the perspective. This can be updated at any time.
This window lets you hide the front or back of the view.
Clip planes is a way to prevent GiD from drawing elements of the geometry or mesh that are either very close to or far from the observer.
By moving the Near plane bar, the geometry that is closer to the viewer is hidden, while moving the Far plane bar hides the geometry that is further from the viewer....
With this window the user is able to enjoy the stereoscopic ( or 3D) experience, and to enable shadow drawing of the model.
Be aware that both options can be costly if the model is big.
Stereoscopic vision
stereoscopic vision3d view
The best experience is achieved with the Perspective view activated, for that purpose the 'Perspective' checkbox has been included in the top right of the window and with the '-->' button the perspective window can be opened. ...
With this option you can choose whether or not the entities should have their labels displayed. As suggested below, there are three options: show all entities with labels, show no entities with labels, or show some with and some without. The options are:
All/All in: All entities in the graphical window will have their labels displayed.
Select->Points, lines, surfaces or volumes: To select some entities of a particular type, choose the desired entity type, then select entities in the usual way ...
With this option, it is possible to choose just some of the points, lines, surfaces or volumes to be drawn. It is useful for making drawings faster or clearer in some instances.
Note: This option is only available in the Right buttons menu (see USER INTERFACE).
With this command GiD draws the direction of lines and the normal of surfaces.
Normals -> Lines: draws the direction of the selected lines. If the line lies on the plane z=0, GiD also displays the normal of the line in 2D.
Normals -> Surfaces: draws the normals of the selected surfaces. There are two ways of viewing surface normals: Normal (as an array) or Colored (the front and back faces of the surface are colored differently). Any surfaces belonging to the plane z=0 will, by default, have their normals oriented towards z positive. In this case, they are defined as anti-clockwise surfaces in 2D....
With this option, it is possible to color-code geometrical entities according to their Higher Entity number. The Higher Entity number is the number of other entities that a given entity belongs to.
If mesh mode is set, you can view the higher entities of mesh nodes.
Draw a contour fill of the curvature of all visible surfaaces on each point and a scale of colors to represent its values
Definition of the surface curvature at a point:
For two-dimensional surfaces embedded in R3, consider the intersection of the surface with a plane containing the normal vector at a point and another arbitrary vector tangent to the surface. This intersection is a plane curve and has a curvature. This is the Normal curvature. The maximum and minimum values of the normal curvature at a point are called the principal curvatures, k1 and k2, and the extremal directions are called principal directions....
The first of these two options lets you save the actual view configuration to a file. That configuration can than be loaded at any time using the View -> Read command.
GiD allows an image to be used as a background for visualization purposes (the supported image formats are gif, png, jpeg, tiff, bmp, tga and ppm). There are the following options:
Fit screen: an image will be shown in GiD's background window; it will be modified if necessary so that it fills the screen correctly.
Real size: the image will not be deformed; the image is placed in a plane. Three points must be entered: two of them to define the line where the bottom line of the image lies, and a stand-up point, which defines the upper direction of the image....
The Multiple windows command lets you have several views of the same project. Different views can be displayed inside the program main window or in supplementary windows.
This menu is for the generation of all the different possible geometrical entities. Usually, new entities are created inside the current layer (see Layers).
Individual points are created by entering each point in the usual way (see Point definition). The points can then be joined together to form lines.
Caution: It is impossible to create new points joining old ones.
The Number option lets you choose the label that will be assigned to the next point created. If a point with this number already exists, the old line changes its number.
NURBS are non-uniform rational B-splines. They are a type of curve that can interpolate a set of points. NURBS can also be defined by their control polygon, another set of points that the curve approximates smoothly....
The data that must be input are the mathematical formulae of the coordinates X(t), Y(t) and Z(t), where 't' is the parameter of the curve, and its value belongs to the interval [ t0-t1 ]. The curve is created by approximation and is a NURBS (Non-Uniform Rational B-Spline) which is created with N points. In GiD these kinds of curves are cubic (order 3)....
A polyline is a set of at least two other lines of any type (including polylines themselves). Every line must share one or two of its endpoints with the endpoints of other lines....
NURBS are non-uniform rational B-splines. They are a type of surface that is defined by its control polygon (one set of points that the surface approximates smoothly), one set of knots for the two directions u and v (a non-decreasing list of real numbers between 0 and 1) and, optionally, one set of rational weights....
The required input data are the mathematical formulae of the coordinates X(u,v), Y(u,v) and Z(u,v), where 'u' and 'v' are the parameters of the surface, and its value belongs to the intervals set in 'u in' and 'v in' respectively. The surface is created by approximation and is a NURBS (Non-Uniform Rational B-Spline), which is created with 'Number of points U' x 'Number of points V' points. In GiD these kinds of surfaces are cubic (order 3)....
Contact surfaces are defined as being between two lines that are physically in the same place, but which have different line and point entities. From a contact surface, it is possible to generate contact elements, to be used by some calculation algorithms, which define a special contact between these two bodies.
Using contact surface entities is like a meshing specification. In this way, equal meshes will be generated for the two lines, ensuring a one-to-one relationship between nodes.
Choose the Contact surface option from the menu, and then select some lines on both bodies....
This option converts all our mesh model (only surface mesh, triangles and quadrilateral) to a geometry model, obtaining a NURBS surfaces based definition. Creates a group of new layers called "Reconstruction", inside you will see two new layers: the first "All Lines And Points" contains lines and point and the second "Reconstructed Nurbs" the surfaces. If some surface couldn't be reconstructed it will appear a third layer called "SurfMeshes Not Reconstructed" containing the remaining parts converted in Surfmeshes, see more infomation about Surf Mesh...
Contact volumes are defined between two surfaces that are physically in the same place but with different surfaces, lines and points. From a contact volume, it is possible to generate contact elements, to be used by some calculation algorithms, which define special contact between two bodies.
Those equivalent surfaces can be in the same location or can be separated by a movement (separated contact volume). The result will be equal meshes, ensuring a one-to-one relationship between nodes.
Choose 'contact volume' from the menu, and then select the surfaces. GiD automatically searches for possible contacts, combining the selected surfaces in pairs....
Note: The 4-sided surface has been substituted by the NURBS surface (see NURBS surface creation). This new entity has all the functionality of the old one.
Note: It is still possible, however, to access to this function with the Right buttons menu (see Tools).
Inside this option, GiD creates as many 4-sided surfaces as it can find. Every new surface will be created in the current layer.
Note:
The 4-sided surface has been substituted by the NURBS surface (see NURBS surface creation
). This new entity has all the functionality of the old one.
Note:
It is still possible, however, to access to this function with the Right buttons menu (see Tools
).
A 4-sided surface is an entity formed by a closed set of four lines in the space. Its mathematical definition is a bilinear Coon's surface. The surface is totally defined by the shape of the lines, with no information about the interior. This means that it will sometimes be necessary to use more surfaces to obtain a good shape definition. ...
Note:
The planar surface has been substituted by the NURBS surface (see NURBS surface creation
). The latter automatically detects if boundary lines lie in a plane and creates a planar NURBS.
Note:
It is still possible, however, to access this function with the Right buttons menu (see Tools
).
A planar surface is an entity formed by a closed set of lines, all of them lying on the same plane. These lines must share some common endpoints....
The deletion of entities can be done in two ways: at one level (point, line, surface or volume) or erasing all entities at once. A selection is made (see ...
By using this command, an existing point is selected and moved. The new position is entered in the usual way (see Point definition). If the new position is an existing point (when using join), GiD will determine the distance between the points and ask if they should be joined. If the answer is yes, both points are converted into one. Any lines of surfaces that include the point in question will be moved accordingly in order that any links are maintained; this may lead to these lines or surfaces being distorted.
The Divide command can be applied either to lines, polylines , surfaces (including trimmed surfaces), and volumes.
Polylines: In the case of polylines, an existing interior point must be chosen. The polyline will be converted into two lines that may or may not be polylines.
Polyline division has the option Angle which allows you to divide the polyline at all the points where the angle between the sub-lines is greater than a given value.
With this option you can edit groups of lines with respect to their topology and shape.
Join lines end points:
With the command Join lines end points, two lines must be selected. GiD determines the distance between the two closest endpoints, draws both points, and asks for confirmation. If one of the lines is a polyline, interior points are also considered. If accepted, the points are converted into one and the lines are distorted. The new point will then take the place of the first line's point....
This command lets you select and alter arcs. Lines that are not arcs are rejected. When you confirm the operation, the arc is converted to a new arc with the same center and in the same plane but opposite the old one. The old arc disappears and the angle of the new arc will be complementary to the angle of the old arc.
Caution: Arcs belonging to higher entities cannot be swapped.
This command lets you select which polylines you wish to explode; lines that are not polylines or have higher entities or conditions are rejected. After confirmation, the polylines are exploded and converted back to their original lines. Polylines then disappear (see Polyline creation).
Edit polyline:
The command Edit Polyline allows you to select which polylines you wish to edit; lines that are not polylines are rejected. It is possible to choose several options for the polylines:...
Tool to modify some NURBS geometric properties, like control points, degree, etc.
Once a NURBS line is selected (use the Pick
button in the Edit NURBS Line window), you can edit its control points (see NURBS line creation
). Select the control points as if they were regular points and enter their new positions in the usual way (see ...
This option converts the selected NURBS lines or surfaces to other ones very similar to the originals but with a less complicated definition. It can be useful when importing data where a control polygon is too complex for GiD to display or mesh quickly.
The Model option performs the operation over all the geometrical entities in the model.
With this option you can select one existing NURBS surface and a set of closed lines that are inside it and that form a hole. The lines may be created by an intersection with another surface. The hole will be added to the existing surface.
To do so, start by creating the interior volumes as independent volumes. After this, click the Hole button and select the outside volume. Then, select the interior volumes that form every hole, one by one. Finish with escape (see Escape).
It is possible to specify 'NoDeleteHoles' to not delete the volumes used to create the holes (or 'DeleteHoles' to delete them)
The Collapse function converts coincident entities, i.e. entities that are very close to each other, into one.
The ImportTolerance variable (see Preferences) determines which entities will be collapsed. Where the distance between two points is less than the tolerance, they will be converted to one. With lines and surfaces, the maximum distance between both entities is calculated and if it is less than ImportTolerance, they are converted to one.
The Uncollapse function lets you select lines, surfaces or volumes and duplicate all common lower entities.
Typically, if two surfaces share one line as an edge, after applying this function to both surfaces, that line and its shared points will be duplicated and every line will belong to a different surface.
This feature is interesting, for example, if you want to disconnect joined bodies or generate a non-conformal mesh with fewer elements than a conformal one.
This option lets you select several lines for which GiD then tries to find as many intersection points as possible. Lines are divided where applicable.
The 'No Divide Lines' option creates an intersection point but does not modify the lines.
You need to select one surface and two points that lie approximately over it. GiD calculates the line intersection between the surface and a plane defined by the two given points and the average normal to the surface of these points.
Note: Planar surfaces cannot be used with this option.
You need to select one NURBS surface and several lines. GiD then calculates the intersection between the surface and the lines. Lines will be divided at the intersection point.
The 'No Divide Lines' option creates the intersection point but does not modify the lines.
The Extend/Divide lines option extends the lines until they reach the surface.
The GiD Volume Boolean Modeler has been designed to accomplish geometric feats such as physically punching a hole through a volume, combining several volumes into one, and creating a new volume from the intersecting part of several separate volumes.
The valid volume boolean operations are:
Union: Fuses several volumes wherever they intersect to create a single, more complex volume.
Intersection: Creates a volume based on the intersecting points of several separate volumes.
Subtraction: Negates a specific portion of a volume to create a hole or indentation....
With this command you can undo any previous commands executed since the the project was last saved or read. To do this, select from the list of operations in the window so that they are highlighted red, and click undo.
Note: There are many settings in GiD that have a predefined value, but that can be modified by the user. They can be accessed in one of two ways. Firstly, by opening the Preferences window from the Utilities pull-down menu, and secondly via the Variables command in the Utilities section of the ...
The first group of Preferences are general options, and are used to set the different ways of working with GiD.
Language: This option sets the language GiD is working in. By now GiD messages are fully translated into English, Spanish, Russian and French. RamTranslator is used to deal with message catalogues for GiD and the translation of problem types (to see more information about RamTranslator visit http://www.gidhome.com...
The second group of preferences are graphical options, and are used to set different ways of visualizing the model. They do not change the geometry or the model information.
Smoothed Elements: If this option is set, when rendering a mesh (see Render) the intersection between elements with a small angle between their normals will be illuminated as if it were a continuous solid. If it is not set, illumination is made considering every element as planar. Variable: LightSmoothedElems. Values: 1,0. Default is 1 (Yes). The angle (in degrees) is the maximum angle between the normals of two elements to allow smooth lighting between them. If the angle is greater than this, one edge is drawn between them. Variable: CosSmoothedElems. Saved as the cosine of this angle. Default is 0.8. ...
The third group of preferences are meshing options.
Quadratic type:This property set the quadratic type of the elements generated. It is applied to the mesh of the whole model. User can choose between three options:
Linear: linear elements are made.
Quadratic: the elements will be quadratic, with a node in the middle of each edge:
The fourth group of preferences are geometry exchange (import and export) options.
Import options:
Automatic Collapse After Import: If this option is set then after reading one IGES file, one global collapse is made. If it is not set, all surfaces and lines will be independent of each other.
Variable: AutoCollapseAfterImport. Default is active (1)....
The seventh group of preferences contains grid options (see Grid).
Show grid lines: If this option is set, grid lines are shown. Variable: Grid(Show). Value: 0,1. Default is 0 (No show). It's possible to show/hide grid with the grid button that is located on the bottom right part of the main window.
Show labels: If this option is set, labels of the major lines are showed....
The sixth group of preferences deals with numerical formats used inside GiD.
Results cache: To allow read big results, without load all of them simultaneously. A maximum result space size could be set. Results could be automatically loaded or unloaded to memory to handle them.
Results state: to try to set to use the last result visualized for the model.
Healthy filter: to filter wrong coordinate numbers, avoiding them....
Layers are a way to split a complex drawing up into separate pieces. The idea is that any entity can belong to one layer or to none (an entity cannot belong to more than one layer). In this way, it is possible to view only some layers and not others. It is also useful for making it easier to select entities in the graphical window....
GMed is an acronym for GiD Medical. GMed is an adaptive and user-friendly graphical user interface for modelling, data input and visualization all types of medical data. GMed is focused in the medical image processing in the biomechanical research field to generating meshes from the medical images, to apply in Computational Fluid Dynamics (CFD) or structural mechanics (stress analysis, flow problems, etc.). GMed contains several tools for the images treatment using advanced images processing.
Although it's main purpose is medical image processing it is not restricted only to work with images coming from that field provided that the data set be stored in one of the format recognized by GMed....
In this menu you can customize GiD toolbars. They can be displayed inside another window, can appear independently in their own dialog box, or can be hidden.
When you select this option, the following window appears:
Within this window you can choose where on the screen the toolbar is to be displayed - inside, outside, top left, bottom right, etc. - or you can switch it off. The GiD toolbars are:...
It is possible to save a window configuration to a file. Then, if GiD is opened again with the -c option (see INVOKING GiD) and the file in question, the windows are opened in the same place and are the same size as before.
A batch file can be read to execute some functions (see Batch file) or to create an animated view of these operations. This latter case can be performed with the Read batch window.
Once a file is selected, it is possible to ***pause it at certain points to highlight interesting parts*** , execute it interactively, and make it stop at interesting points. To allow all the movements (rotations and so on) be executed in the same way as originally, the Write rotations in batch: option must be flagged in the preferences window (see ...
Comments can be added to images created with GiD by using this command. Click Apply to display the text on the screen as it will appear when printed - either to a file (see Print to file) or otherwise; comments can be changed at any time by clicking the Comments button in the Utilities menu (either pull-down or Right buttons menus).
This windows lets you create animations while using GiD. Any of these formats can be selected: MPEG, AVI True Color, AVI 15bpp (reduced number of colors: 32768) and GIF. AVI with MJPEG compression is also supported. After giving a name and a delay time between frames (for 20 frames per second, a delay of 1/20 = 50 ms. should be entered) the process can be started by clicking on the start button (film roll and arrow icon); the green LED will change to red....
Windows 'Macros' allow you to create sequences of commands and give them a name. This group of commands can also be recorded from one execution set inside the program.
It is possible to assign a keyboard shortcut to a given macro.
Note:
Macros are considered as a user preference and not related to the active model. So, to transfer a set of macros from one user to another it is necessary to copy the appropiated 'Macros.tcl' file (its location is platform dependent) ...
For those functions where some entities are to be selected (creation of a surface or a volume, copying entities, etc.), it is possible to use the Selection window. The selection window lets you take control of the selection process.
This option creates a report in html format to which figures, comments, titles, etc. can be added. This report can be saved to a file and then reloaded in another GiD session where it can be edited or have more information added to it.
This command works like Copy but moves the entities instead of copying them. The program automatically checks to see if any of the entities must be copied instead of being moved (for example, if they also belong to other higher level entities) and performs the appropriate operation.
Options like Extrude, Multiple copy and Create contacts are disabled for movements.
The List command gives information about the selected entities. This information is read-only.
If the Mass option is checked, information about physical properties is given: lengths of lines, center of mass, areas of surfaces, volumes of solids. It works for both the geometry and the mesh.
All this information can be sent to the active report (see ...
When creating new entities, the label of the new entity will be the lowest number greater than 0 that still does not exist for this entity type. If an entity is deleted, a gap is left in the labels list. This gap will be filled with a new entity, but it is also possible to renumber the geometry, changing the previous entity labels. There are no problems with materials and conditions applied to entities.
In geometry mode, the renumbered entities are the geometrical ones.
This command gives the label and coordinates of an existing or new point. Different options for getting information about an existing point are available in the Contextual
menu.
With this option you can select one entity (a point, line, surface or volume), and a pair of crossed red lines will signal the center of the entity in the graphical window.
They must be existing entities, except the special case of points or nodes, where they can be existing or defined with any of the usual methods.
The Superpose Lines option (in the Contextual
menu) is useful when in render mode. Depending whether it is set or not, the crossed red lines will either be in front of the object or partially hidden by the model. ...
This command can be applied to lines or surfaces (in geometry mode) or to elements (in mesh mode). A selection is made (see Entity selection) and the orientation of the selected entities is inverted.
Viewing commands (zoom, rotation, etc.) can be applied and the normals will remain on the screen.
When this command is applied to surfaces or mesh elements, you can choose one of the following options:
Select: Inverts the direction of the normals of the selected surfaces....
This option checks the coherence of the database information. Only use it if there are problems. When used, a window notifies you of any repaired items and may give some warnings about incorrect entities.
All the data that defines the problem and that is managed in the data menus, depends on the Problem Type and will change for every different problem type. The following help will describe the common interfaces to all the possible data.
Data for a problem is defined by the following parameters: conditions (see Conditions), materials properties (see Materials), units (see Data units), problem data (see ...
This option lets you choose between all installed Problem Types. When selecting a new problem type, all information about materials, conditions and other data parameters that were already selected or defined is lost.
Note: When defining a new problem type which is not already installed, it must be selected by other means. One possibility is to select Problem type -> Load... . Another possibility is to select "data defaults problemtype" in the Right buttons menu or enter it in the command line....
This option can be found inside the Problem Type menu and is useful for updating a model from an old problem type to a newer one that is similar to the first.
When converting, it tries to maintain all the conditions and materials assigned to the geometry or mesh. Also, it tries to maintain the rest of the data.
It will typically be used when a problem type has been updated and it is necessary to reuse a model defined with the old version.
The Load... option allows you to load a previously installed problem type from the current or another directory. This possibility is useful when developing a new problem type which cannot be installed until it is finished, or if the developer does not have permission to write to the Problem Types directory.
This option unloads the problem type currently in use.
Sometimes it is easier to work with a model that does not have an associated problem type. It is also useful for sending a model to another user who does not have the problem type in question.
Conditions are all the properties of a problem (except materials) that can be assigned to an entity.
An example would be the boundary forces and displacement constraints in a solid mechanic analysis or initial velocities in a CFD analysis. Information about contact between master-slave nodes can also be considered as conditions.
Caution: Once a mesh has been generated, any changes made to the condition assignments require you to regenerate the mesh in order to transfer these new conditions. If this new generation has not been performed, GiD will warn you when the data for the analysis is being written....
A condition is assigned to geometric entities or layers that have the given field values.
If you are using the AssignCond command in the Right buttons menu, the Change option allows you to define the field values. Do not forget to change these values before assigning. Selecting DeleteAll erases all the entities that have this particular condition assigned.
Conditions can be assigned both to the geometry and to the mesh, but it is advisable to assign them to the geometry because in this way the conditions will then be transferred automatically to the mesh. If assigned to the mesh, any re-meshing will cause the conditions to be lost....
The DrawAll option draws all the conditions assigned to all the entities. This means that a graphical symbol or condition name will be drawn over every entity that has this condition.
If one particular condition is selected, you can choose Draw for just one field. Draw is like DrawAll, but for one particular condition only. If one field is chosen, the value of this field is written over all the entities that have this condition assigned.
If the condition has any field which refers to the type of axes, the latter can be visualized by means of Draw local axes....
When using the UnAssign window, you can choose between several possibilities:
Unassign one condition from some selected entities.
Unassign one condition from all the entities that may have this assigned.
Unassign all conditions of a book from all the entities that may have them assigned.
Unassign all conditions from all the entities that may have them assigned.
When using the command line or the Right buttons menu, UnAssign works as the fourth option above, i.e. all conditions. To unassign only one condition, use the DeleteAll command (see ...
For any problem that needs a definition of materials, there is a database of existing materials that can be assigned to entities. You can also create new materials derived from existing ones and assign them as well.
Caution: Once a mesh has been generated, any changes made to the assigned materials require you to regenerate the mesh or reassign these materials to the mesh directly. If only the material definition is changed (i.e. some field value) then is not necessary to re-mesh again.
This option is used for assigning a material to some selected entities.
When working in geometry mode, the kind of entity to which you wish to assign a material must be selected, i.e. point, line, surface or volume; when working in mesh mode, you select directly the elements to which the material is to be assigned.
Note: A material cannot be applied over nodes; a material only assigned to points will be transferred to 1-node elements if generated, but not to nodes themselves....
This option draws a color indicating the selected material for all the entities that have it assigned. It is possible to draw just one material type or, alternatively, to draw all materials. To select just some of them use a:b and all material numbers that lie between a and b will be drawn.
When using the UnAssign window, you are presented with several possibilities:
Unassign one material from some selected entities.
Unassign one material from all the entities that may have this assigned.
Unassign all materials from all the entities that may have them assigned.
When using the command line, UnAssign works as the third option here, i.e. all materials. For only one material, use UnAssignMat (see Assign material)....
When using the NewMaterial command, a new material is created taking an existing one as a base material. Base material means that the new material will have the same fields as the base one. Following this, all the new values for the fields can be entered in the command line.
It is also possible to redefine an existing material.
To create a new material or redefine an old one using the materials window, write a new name or an existing one and change some of the properties. Then click Accept.
It is possible to import and export materials between the model database and an external one. Typically, one centralized database of materials is maintained and every new model gets its properties from there.
Note: If you wish to exchange materials with the problem type database, it is necessary to check that you have permission to read/write in that directory.
Problem data refers to all the data that is associated generally with the problem. This means that it is not related to a geometrical entity and it does not change for every interval of the analysis.
It can be entered with the ProblemData command in the Right buttons
menu or in the Problem Data window.
If entered in a window, the data is not accepted until the you click the Accept button.
This data can be entered before or after meshing....
Data units refer to the units defined in the problem. This option only appears if the problem type loaded has units defined.
You have to declare the length units of the current model and the unit system to be used when writing coordinates and data properties in the calculation file (values will be converted from the current units to the selected system units).
It is possible to set a user-defined unit system, but this feature can be disabled (see Unit System file (.uni) from Customization Manual). ...
Intervals are a way of separating information into several groups; information for every group can also be duplicated, if desired. When a new interval is defined, you can choose whether or not to copy all the new information about conditions assigned to entities.
Therefore, the correct way to work is to define all the conditions first and afterwards create the new intervals.
The options are:
New: You can define as many intervals as you wish using this command. When creating a new one, you can choose whether or not to copy the assigned conditions. To copy them, conditions must already have been assigned (see ...
With this option, GiD lets you define new coordinate reference systems. They can be writen not only using cartesian reference systems, but also with reference to Euler angles. All user-defined systems are automatically calculated and can be visualized one by one or all together.
There are several ways to define new local axes:
3 Points XZ: Enter three points that corresponds to the origin, the X-direction and the Z-direction. The origin and the last introduced point define the Z-axis, whereas the second point indicates the side of the x-z plane where the point lies....
Generating a mesh is the process by which a finite element mesh is calculated from the geometry definition. This mesh will be used for the FEM analysis at a later stage. Conditions (see Conditions) and materials (see Materials) assigned to geometric entities will be transferred to the nodes and elements of the new mesh.
What is meshed and how it is meshed is controlled by some default options which can be changed with the commands described later.
The generation does not depend on whether layers are ON or OFF at the moment of generation (see ...
Note: Size is given by the average side length (edge) of the corresponding mesh element.
Assign sizes on points, lines, surfaces or volumes:
It is possible to assign different sizes to different entities of the mesh. This means that in the vicinity of these entities, the generated elements will be approximately of that size. All the entities that do not have an assigned size when meshing take the default one. Points do not take any size if none is given.
A structured mesh is defined as a mesh where all the nodes have the same number of elements around them.
The size of the elements is defined in a different way than for a non-structured mesh. In this case, the mesh is not defined by the size but by the number of elements that are required on every line. This number must be the same for all lines that are opposite each other on each surface. When meshing volumes, this definition must be the same for opposite surfaces.
To create a structured mesh, choose Structured -> Volumes/Surfaces/Lines. After selecting escape, the number of elements per line is given. Later, lines can be selected and related lines (when dealing with surfaces or volumes) are added or deleted from the group. This process can be repeated as many times as necessary until all lines have a new value. Lines with no numbering given will have two elements over them. All non-selected lines will also have two elements by default....
By default, all partitions in one structured line have the same approximate length. This command lets you select one line, which will be shown in the graphical window with an arrow indicating its direction. You then have to enter a positive or negative weight. If the weight is positive the elements will be concentrated towards the extremities of the line; if negative, the elements will be repelled.
A semi-structured mesh is a mesh that is structured in only one direction of the volume and is unstructured in the other two directions. For example, in a prismatic volume, the meshing on the sides of the object could be structured, while the meshing on the surfaces at each end could be unstructured. The surfaces on both ends must be topologically equal.
Depending on the element type selected for each surfaces of the volume, the elements will be hexahedra, prisms or tetrahedra.
A boundary layer mesh is one mesh attached to the boundary, and which has a certain distribution of nodes separated from the boundray following a certain stretching function. The streching function and the grow factor of the boundary layer meshes of a model can be set in Preferences->Meshing.
User can define two main properties to the boundary layer meshes of each geometrical entity: First layer height and Number of layers. When selecting the entities which will have boundary layer mesh a window shows a schematic picture, where user can see the distribution of heights of each layer, and the total height of the boundary layer mesh when the assigned properties are set....
With this command, the type of element you wish to use is selected. It is only necessary to do this when the element type is different from the default (see MESH).
The types are as follows:
Default: For surfaces and volumes. This option lets GiD assign a compatible element type to geometric entities, assigning the default ones if possible (see MESH).
GiD provides five different criteria to generate the mesh. The Default option skips meshing the boundaries, that is, lines for surface meshes and surfaces for volume meshes.
The Mesh option lets you choose the entities to be meshed, while the No Mesh option does the opposite.
The Skip option forces GiD to skip a geometrical entity when meshing (so the entity will not have mesh), while the No Skip option forces GiD not to skip the geometrical entity (so the entity will have mesh) when the RJUMP surface mesher is used (see ...
When sizes are assigned to points, lines, surfaces or volumes using the Assign Unstruct sizes option, it is possible to draw the different assigned sizes in different colors.
EXAMPLE
In the following example some different sizes are assigned to surfaces. Sizes of 3, 5 and 6 are assigned depending on the surface.
With this option you can see which element types have been assigned to each geometric entity. If no element type has been assigned, it is shown as Default (see MESH).
With this option you can see the entities that GiD has either been forced to mesh or forced not to mesh (see Mesh criteria). If the meshing criteria have not been assigned to an entity, it is shown as Default (see MESH).
With this option you can see what kind of mesh will be generated for geometrical entities, i.e. Unstructured, Structured or Semi-Structured. If no level of structure has been assigned, it is shown as Default (see MESH).
With this option you can see which lines and points will be skipped when meshing using the meshing preferences set at that moment (see Preferences -> Meshing), and the lines and points set as Skip or NoSkip mesh criteria (see Mesh criteria).
With this option you can see the first layer height of the boundary layers set in the model. In '2 dimensional' option the lines from wich the boundary layer will grow are shown, and in '3 dimensional' the surfaces.
In cases where two boundary layer meshes grows from the same geometrical entity (one for each side), the minimum value of the first layer heigt is shown.
When everything is ready for mesh generation, select this command. If there is a previously generated mesh, GiD asks if this should be erased. It will be lost from the memory, but will remain on the disk until the project is next saved (see Save).
The mesher or mesher combination can be chosen in preferences (see Preferences).
Next, GiD asks for a general element size which will be applied to all lines, surfaces and volumes that do not have one previously defined (see ...
To split elements, select them in the usual way (see Entity selection), and then press escape (see Escape) to perform the action. Triangles can be split into triangles, quadrilaterals into two or four triangles, tetrahedra into tetrahedra, hexahedra into tetrahedra, and prisms into tetrahedra.
When splitting triangles, the new nodes can be located in the mid-edge or with an enhanced interpolation (modified Butterfly scheme) in order to obtain a smooth mesh....
To smooth elements, select them in the usual way (see Entity selection), and then press escape (see Escape) to perform the action.
Currently only triangles, tetrahedra and hexahedra can be smoothed.
In the case of tetrahedra and hexahedra, element connectivity is conserved after the smoothing; however, with triangle elements this may be modified during the smoothing process....
This option opens the mesh errors window. This window presents a list of the entities that GiD could not mesh, and some information about the problems that occurred during the meshing process. By right-clicking over an item in the list, advice will be displayed about how to solve the meshing problems for each geometrical entity.
This option opens a window that shows information about the quality of the mesh elements.
There are six criteria used to measure the quality of the elements:
Minimum angle: The quality criterion is the minimum angle in surface elements and the minimum dihedral angle for volume elements. This means that elements with a small angle are considered to be of a worse quality than ones with bigger angles....
This option load the meshing preferences of the model. This preferences can be also loaded automatically when loading a model if the general preference 'Get meshing preferences from model' is set (General).
With this menu, you can initiate and manage the analysis of a problem. hereafter referred to as a "process". You will see in the sections that follow that several analyses, or processes, can be run at the same time.
This option begins the process module on a remote machine. Once it is selected, you can continue working with GiD as usual.
Note: ProcServer with the same model problem type must be installed and running on the remote machine in order to use this option. (ProcServer is not included with GiD.)
Select a process that is currently running and click this option to open a window that shows information relating to the process, such as iterations, convergence, etc. Clicking Close will close the window, but will not halt the process.
Selecting this option opens a window in which a list of all the running processes is shown, along with some useful information like name, starting time, etc.
The buttons in this window let you control some running process features, such as terminating the process (Terminate), starting a remote calculation (Start remote), or setting remote analysis properties (Remote...). These remote analysis properties are shown in the next figure....
GiD provides a help system based in html format. In the same window you can access the following sections: GiD Help, GiD Customization, FAQs, GiD Tutorials and What's New. These contents can also be accessed directly from Help Menu. The help window provides three ways of accessing a given topic: a) through a table of contents shown as a tree, b) through an indexed list of terms appearing inside the help, and c) through a search engine.
In order to get the most of GiD, you need to register a password that can be obtained from http://www.gidhome.com. From this site you can obtain a permanent or temporary password. The password must be typed in the window shown below.
If you have previously registered your current copy of GiD (official versions only), the password can be reloaded by clicking the ...
In the same way that some of GiD's capabilities have restricted access before it is registered, so not all problem types are available without registration. The layout of the Register Problem type window is shown below:
If a problem type has been registered previously, the password can be reloaded by clicking ...
GiD provides a default validation when registering a module or problem type. This consists of checking that the password is not empty. If the password is valid, GiD appends a line to the file <problem type>/password.txt similar to this:
hostname password # 2008 01 19 Password for Problem type '/pathroot-to-problem-type/problemtype.gid'
This default validation can be overridden, but this involves Tcl programming. For a description of how to provide a custom password validation see ValidatePassword node from Customization Manual....
Several useful options can be found in the Files menu.
New : Clears all postprocess information present in GiD.
Open : Reads postprocess information in GiD. If, for instance, the postprocess files are 'PostFile.msh' and 'PostFile.res' and a view file is present with the name 'PostFile.vv' then it will be also read.
Open multiple : With this option you can load multiple meshes (pairs of .msh and .res, or .bin files) into GiD. This is useful, for instance, when performing an analysis where some or all steps require re-meshing. ...
Inside the Utilities menu, the options Id, Signal, Distance and Calculator have the same functionality as in preprocessing mode (see UTILITIES). Other options in the Utilities menu are slightly different.
Status: A window appears showing the general postprocess status: number of meshes, elements, etc.
Here you can cut and divide volumes, surfaces and cuts. A cut of a volume mesh results in a cut plane. The cut is done for all the meshes, even those that are switched Off. When cutting surfaces, a line set will be created. Here only those surfaces that are switched On are cut.
Another feature is that a cut can be deformed, if meshes are also told to do so (see Deform Mesh). A cut of a deformed mesh, when changing to the original shape, will be deformed accordingly....
As points and lines can be viewed, there are several interesting options for each of them.
Menu: Options->Geometry->Point options...
Point options:
Here you can select whether to draw the points Quick, Nice or with the center of a Texture glued to the point. Quick: points will be drawn as big dots. Nice: points will be drawn as little spheres (quadrilateral meshes). For every draw style, the Point Size can be changed, but ranges vary between Quick, which depends on the graphics library, and Nice and Texture. When the Nice style is selected, the Nice detail level can be adjusted. The number represents the number of vertical and horizontal subdivisions of a sphere....
Below in an example of the View Style window, where almost all the interesting visualization options can be adjusted. It only deals with meshes, sets or cuts, and not with results.
Selecting Volumes, Surfaces and/or Cuts, you can switch them On and Off, Delete them or rename them. By clicking on a Volume, Surface or Cut, and pressing Color... you can adjust the appearance of the selected set; you can change the color, including the Ambient, Diffuse, Specular, Shininess and transparency components, and return it to its Default color. The Diffuse component is used for all the representations, while the others (Ambient, Specular and Shininess) have more effect in Render visualizations....
In GiD it is also possible to assign a texture to a Set. Inside the Utilities -> Texture menu there are several options:
View No / Fast / Nice: switches between viewing the textures over the sets or not.
When the texture is small and a pixel of the textures must be drawn over several pixels on the screen, the Fast mode just draws the pixels using the 'nearest neighbor' policy, while the Nice mode tries to interpolate the colours of the pixels from the original....
Another feature in GiD is the calculation of the involving mesh of a set of points or nodes. To switch the visualization of this mesh on and off just select Options -> Geometry -> Covering mesh. After saying 'Yes' to the visualization of the covering mesh, you will be asked for a number. This number is the distance between the covering mesh and the points.
This option is not only available for points, but also for every mesh/set present in GiD.
In postprocess a new fonts management system has been implemented. Now GiD uses directly True Type Fonts (R) to draw text inside the postprocess graphical windows.
This allows to draw the characters with smoothed edges.
The user can select the fonts for the diferent text objects with the Fonts panel in the preferences window, when the postprocess mode is active.
From this panel, the edge drawing mode of the leters can also be set between 'Smooth edges' and 'Sharp edges'....
This option allows the visualization of colored zones, in which a variable or a component varies between two defined values. GiD can use as many colors as permitted by the graphical capabilities of the computer. When a high number of colors is used, the variation of these colors looks continuous, but the visualization becomes slower unless the Fast-Rotation option is used. A menu of the variables to be represented will be shown, and the one that is chosen will be displayed using the default analysis and step selected.
Vectors will be unfolded into their X, Y, and Z components and module. Symmetrical matrix values will be unfolded into the Sxx component, Syy component, Szz component, Sxy component, Syz component and Sxz component of the original matrix and also into the Si component, Sii component and Siii component in 3D problems or angular variation in 2D problems. Any of these components can be selected to be visualized....
This display option is quite similar to Contour Fill (see Contour Fill), but here the isolines of a certain nodal variable are drawn. In this case, each color ties several points with the same value of the variable chosen.
Here the configuration options are almost the same as the ones for Contour Fill (see Contour Fill), with the only difference being that the number given in the Number of Colors option will be used as the number of lines for this contour lines representation....
This is the same as the Contour Fill visualization type, but the coloured areas are created following a 'Result range table' specified in the results file (see Result Range Table from Customization Manual), and the names of these areas are visualized as text labels.
Contour ranges is supported for results defined over nodes or gauss points.
With this option you can see the minimum and maximum of the chosen result.
Show mix max is supported for results defined over nodes or gauss points.
Note: This minimum and maximum can be absolute - for all the meshes/sets/cuts - or relative (local) to the ones displayed. This can be selected from the pull-down menu Options -> Contour -> Set Limits.
This option displays a menu with results from vectors and matrices (where the principal values have been previously evaluated by the program). From the menu of variables, choose the one you wish to see displayed; it will be shown with the default analysis and step (this can be changed with the Default Analysis/Step option in the menu). Once a result is chosen, the program will display the nodal vectors of the chosen result. The vectors that are drawn can be scaled interactively. The factor can be applied several times and every time it changes to the new input value.
Here a surface is drawn that ties a fixed value inside a volume mesh; for surface meshes a line is drawn. To create isosurfaces there are several options:
Exact:
After choosing a result or a result component of the current analysis and step, you can input several fixed values and then for each given value an isosurface is drawn.
Automatic:
Similarly, after choosing a result or a result component, you are asked for the number of isosurfaces to be created. GiD calculates the values between the Minimum and the Maximum (these are not included). ...
With this option you can display a stream line, or in fluid dynamics, a particle tracing, in a vector field. After choosing a vector result, using the default analysis and step selected, the program asks you for a point from which to start plotting the stream line. This point can be given in several ways:
The best way to choose initial points for the stream lines is to cut the mesh through the place where the user wants the stream lines, and then select the nodes of this cut.
Here you can draw graphs in order to take a closer look at the results. Several graph types are available: point evolution against time, result 1 vs. result 2 over points, and result along a boundary line. You can also save or read a graph (see Files menu). The format of the file will be described later (see Graph File Format).
In the View Results -> Graphs pull-down menu, there are the following options:
From this window diferents kinds of graphs can be created. The colour, line style, names of these graphs can be also changed from this windows. A grid can be drawn as reference, and several other options can be personalized.
From this panel, following options are present:
Point evolution: a graph of the evolution of the selected result along all the steps, of the default analysis, is created after pressing the 'Apply' button and selecting some nodes or points. ...
This option uses a result component, or a scalar value, and draws a 3D surface above the mesh following the normals of this mesh. It can be seen as an extrusion of the mesh along its normals with the result as factor, like the beam diagrams but with surfaces.
Result surface is supported for results defined over nodes.
With the Show elevations option inside the menu Options -> Result Surface, you can choose how the elevations (lines or faces that connect the result surface with the underlying mesh) are drawn:
Volumes, surfaces and cuts can be deformed according to a nodal vector and a factor. When doing this all the results are drawn on the deformed volumes, surfaces and cuts. In GiD this is called Main Geometry. Thus, when the Main Geometry is deformed, results are also drawn distorted; and when Main geometry is in its original state, results also drawn in their original state.
Deformation is supported for results defined over nodes.
This result visualization option is only active when line elements are used in the mesh, and will only be represented over these line elements. When using this result visualization option, graph-style lines will be drawn over the line elements.
When drawing a Scalar Diagram , the graph-style lines are drawn on a plane parallel to the screen (with its normal vector pointing out of the screen) when this result view is selected. The positive 'axis' will be the vector resulting from the cross product between this normal vector and the one that the line defines. ...
With this window a little bit of automatization has been done to create animations inside GiD. Nowadays, almost all results visualizations are animated. Only stream-lines are not automatized along all the steps of the current analysis.
Some animations can be done with combined results visualization, or separate analisis, for instance an isosurface animation from OLS result of ODDLS analysis with a contour fill of Pressure of the RANSOL analysis can also be done with this window. the only constraint is that the same number of steps and the same value of the steps should be present in both analysis....
With this window, which appears under Windows -> Several Results, you can select whether to view the results one by one, as usual, or to view some results visualization types at once, e.g. a contour fill of pressure and velocity vectors at the same time. From this window you can also delete the undesired results visualizations. After selecting the desired behaviour, press the Apply button.
While displaying results, comments can be automatically generated by switching On the Automatic checkbox in the Comments window, which appears by selecting Utilities -> Graphical -> Comments.
If this option is selected and the comment lines are empty, the program will create its own automatic comments, like these ones:
The following operators needs two operands: +, -, * and /.
The first operand is a result and the second operand can be a scalar, a vector or a result. These operations are done component-wise, and so, both results should be of the same type....
With this window the user can create graphs from other graphs.
The following operators needs two operands: +, -, * and /.
The first operand is a result and the second operand can be a literal or a graph. These operations are done on the selected components and the graphs needs to have the same number of values....
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