Import |
GiD lets you import geometrical models or meshes in the following formats.
IGES |
Menu: Files->Import->IGES...
With this option it is possible to import a file in IGES format (version 5.3); GiD is able to read most of the entities, which are:
Entity number and type (Notes)
100 Circular arc
102 Composite curve
104 Conic arc (ellipse, hyperbola and parabola)
106 Copious data (forms 1, 2, 12 and 63)
108 Plane (form1 bounded)
110 Line
112 Parametric spline curve
114 Parametric spline surface
116 Point
118 Ruled surface
120 Surface of revolution
122 Tabulated cylinder
123 Direction
124 Transformation matrix (form 0)
126 Rational B-spline curve
128 Rational B-spline surface
134 Node
136 Element
140 Offset surface entity
141 Bounded entity
142 Curve on a parametric surface
143 Bounded surface
144 Trimmed surface
184 Solid assembly
186 Manifold solid B-rep object
190 Plane
192 Right circular cylindrical surface
194 Right circular conical surface entity
196 Spherical surface
198 Toroidal surface
308 Subfigure definition
314 Color definition
402 Associativity instance
406 Property entity
408 Singular subfigure instance
502 Vertex
504 Edge
508 Loop
510 Face
514 Shell
The variable ImportTolerance (see Preferences ) controls the creation of new points when an IGES 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.
Entities that are read in and transformed are not necessarily identical to the original entity. For example, surfaces may be transformed into planes, Coons or NURBS surfaces defining their contours and shape.
DXF |
Menu: Files->Import->DXF...
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 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.
You can use the Collapse function (see Collapse ) to join more entities.
Parasolid |
Menu: Files->Import->Parasolid...
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.
ACIS |
Menu: Files->Import->ACIS...
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.
VDA |
Menu: Files->Import->VDA...
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.
The Collapse function (see Collapse ) can be used to join more entities.
Rhinoceros |
Menu: Files->Import->Rhinoceros...
With this option it is possible to read Rhinoceros 4.0 CAD files. This files have the .3dm extension.
Shapefile |
Menu: Files->Import->Shapefile...
With this option it is possible to read a GIS file written in ESRI Shapefile format (version 1000). Shapefiles have the .shp extension.
XYZ points |
Menu: Files->Import->XYZ points...
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.
KML |
Menu: Files->Import->KML...
With this option it is possible to read files with the format KML. It uses in georeferenced images.
The variable ImportTolerance (see Preferences ) controls the creation of new points when the file is read.
NASTRAN mesh |
Menu: Files->Import->NASTRAN mesh...
With this option it is possible to read a file in NASTRAN format (version 68), with GiD accepting most of its entities, which are:
Entity name ( Notes)
CBAR CBEAM CROD CCABLE CBUSH CELAS1 CELAS2 CELAS3 RBAR (translated as 2 node bars)
CQUAD4 CQUADR
CHEXA
CTETRA
CPENTA
CTRIA3 CTRIAR
CONM1 CONM2 (translated as 1 node element)
CORD1C CORD1R CORD1S
CORD2C CORD2R CORD2S
GRID
There are two options that can be used when reading a mesh if GiD already contains a mesh:
The properties and materials of elements are currently ignored, because of the difficulties in associating the NASTRAN file properties with the requirements of the analysis programs. Therefore, you have to assign the materials "a posteriori" accordingly. However, in order to make this easier, the elements will be partitioned in different layers, each with the name PIdn, where n is the property identity number associated with the elements as defined in the NASTRAN file. Note that CELAS2 elements do not have associated property identities so these will be created by default when the file is read.
STL mesh |
Menu: Files->Import->STL mesh...
With this option it is possible to read a mesh in STL format. The STL binary format is also supported.
The variable ImportTolerance (see Preferences ) controls the creation of new points when the file is read.
VRML mesh |
Menu: Files->Import->VRML mesh...
With this option it is possible to read a mesh in VRML 2.0 format. The compressed gzip format is also supported.
3DStudio mesh |
Menu: Files->Import->3DStudio...
With this option it is possible to read a mesh in .3ds
3DStudio format.
CGNS mesh |
Menu: Files->Import->CGNS...
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.
GiD mesh |
Menu: Files->Import->GiD mesh...
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:
mesh dimension 3 elemtype tetrahedra nnode 4
coordinates
1 0 0 0
2 3 0 0
3 6 0 0
4 3 3 0
5 3 1.5 4
6 3 1.5 -4
7 1.5 0 2
end coordinates
elements
1 1 2 4 5 1
2 2 3 4 5 1
3 1 4 2 6 1
4 2 4 3 6 1
5 1 2 5 7 1
end elements
The code nnode means the number of nodes per element and dimension can be either:
Where elemtype must be:
For sphere and circle elements after the connectivities the radius must be specified, and for circle elements also the three normal components could be written (z direction is considered by default)
Every element may have an optional number after the definition of the connectivity. This number usually defines the material type and it is useful to divide the mesh into layers to visualize it better. GiD offers the possibility of dividing the problem into different layers according to the different materials through the option Material (see Layers ). For sphere elements is necessary to additionally specify its radius.
Note: The = sign is optional, but if it is present it is necessary to leave a space.
If it is necessary to enter different types of elements, every type must belong to a different mesh. More than one mesh can be entered by writing one after the other, all of them in the same file. The only difference is that all meshes except the first one have nothing between coordinates and end coordinates. They share the first mesh's points. Example: to enter tetrahedron elements and triangle elements,
mesh dimension = 3 elemtype tetrahedra nnode = 4
coordinates
1 0 0 0
2 3 0 0
3 6 0 0
4 3 3 0
5 3 1.5 4
6 3 1.5 -4
7 1.5 0 2
end coordinates
elements
1 1 2 4 5 1
2 2 3 4 5 1
3 1 4 2 6 1
4 2 4 3 6 1
5 1 2 5 7 1
end elements
mesh dimension = 3 elemtype triangle nnode = 3
coordinates
end coordinates
elements
1 1 2 4 1
2 2 3 4 1
3 1 4 2 1
4 2 4 3 1
5 1 2 5 1
end elements
Surface mesh |
Menu: Files->Import->Surface mesh...
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.
Ply |
Menu: Files->Import->Ply...
With this option it is possible to read files with format Ply. Generally, it saves ploygons.
The variable ImportTolerance (see Preferences ) controls the creation of new points when the file is read.
VTK Voxels |
Menu: Files->Import->VTK Voxels...
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.
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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:
XYZ nodes |
Menu: Files->Import->XYZ nodes...
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.
Batch file |
Menu: Files->Import->Batch file...
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:
geometry create line
3.7 4.5 8
2 5 9
4,5,6
...
1 7 0.0
escape
A batch file can also be loaded into GiD by giving its name with the option -b when opening GiD (see INVOKING GiD ). Another way to read batch files to create dynamic presentations is with the Read batch window (see Read batch window ). One GiD session can be registered in a batch file. This can be useful for checking the batch commands or to repeat one session (see Preferences ).
BATCH FILE COMMANDS
There are some special commands to be added to a batch file that are treated differently from regular GiD commands. Their format is one or several words after the control string ***** (five asterisks) and everything in one line.
*****OUTPUTFILENAME filename
filename is substituted with a real file name where all the session warnings (those which appear in the GiD messages warning line) are written. This can be useful when running GiD in batch mode with the option -n (see INVOKING GiD ) and GiD output is desired.
*****TCL tcl_command
Note: If this command is used in a batch file and GiD is invoked with the option -n , it will not work. So that Tcl commands are executed when GiD is run without a window, you should use the -n2 option (see INVOKING GiD ).
geometry create line 1,2
*****COMMENTS -this is a comment-
2,3 escape
geometry create line 1,2
*****PRINT -This is a message that will appear in the messages line-
2,3 escape
geometry create line 1,2
*****PRINT1 -This is a message that will appear in a new window-
2,3 escape
Insert GiD geometry |
Menu: Files->Import->Insert GiD geometry...
This command lets you insert one previously created GiD model inside another one. Entities from the old and the new model are not collapsed.
You can perform one Collapse operation (see Collapse ) to join the old and new models.