Edit

These are the GiD editing options for geometrical entities:

Move point

Menu: Geometry->Edit->Move point

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.

Divide

Menu: Geometry->Edit->Divide

The Divide command can be applied either to lines, polylines , surfaces (including trimmed surfaces), and volumes.

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.

Caution: An interior point must belong to the first level of a polyline (see Polyline creation ).

In the case of lines and surfaces, once the entity has been selected the division can be done in several ways:

Note: After the division, the old entity disappears and the new entities are created.

Line operations

Menu: Geometry->Edit->Line operations

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.

(See Move point for another method of converting two points to one.)

Caution: The second selected line cannot have higher entities (the second point is moved to the first).

Force to be tangent:

With the command Force to be tangent, two lines (which share at least one point) must be selected. They must be NURBS lines, otherwise they will be rejected. You are asked to enter the maximum angle between lines to accept the operation, and GiD will modify the selected NURBS lines and force them to be tangents at their common point.

Swap arc

Menu: Geometry->Edit->Swap arc

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.

Polyline

Menu: Geometry->Edit->Polylines

Explode polyline:

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:

Note: If one condition is assigned to one interior point of a polyline (see Conditions ), one node of the mesh will be placed over that point.

SurfMesh

Menu: Geometry->Edit->SurfMesh

Select one or several surface meshes (see Surface mesh ). The options are:

Edit NURBS line/surface

Menu: Geometry->Edit->Edit NURBS

Edit NURBS line:

Tool to modify some NURBS geometric properties, like control points, degree, etc.

Edit NURBS line window

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 Point definition ).

The Influence factor affects the movement propagation of the neighboring control points.

Available options:

Edit NURBS surface:

Edit NURBS surface window

Once a NURBS surface is selected (use the Pick button of the Edit NURBS Surface window), you can edit its control points intereactively (see NURBS surface creation ). Select the control points as if they were regular points and enter their new positions in the usual way (see Point definition ).

Available options:

Control polygon of a NURB surface

The Movement type menu of the Edit NURBS Surface window determines the way the selected knots will move. This movement can be along an axis (X-Axis, Y-Axis, Z-Axis), can describe the Normal of the surface (Normal), can follow the screen movement of the mouse (Screen), or the new location of the knot can be defined by introducing the coordinates of a point (Point).

Note: The Insert knot and Degree elevate options can be chosen for either the u or the v parameter directions.

Convert to NURBS line/surface

Menu: Geometry->Edit->Convert to NURBS

This option converts the selected lines or surfaces to NURBS lines or NURBS surfaces.

Note: Some algorithms only work with NURBS entities.

Simplify NURBS line/surface

Menu: Geometry->Edit->Simplify NURBS

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.

Hole NURBS surface

Menu: Geometry->Edit->Hole NURBS surface

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.

Hole Volume

It is possible to add holes to a volume.

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)

Collapse

Menu: Geometry->Edit->Collapse

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.

Select the type of entities - point, line, surface or volume - when in geometry mode. All the lower entities that belong to the selected entities will automatically be computed. On pressing escape, the collapse operation will be performed.

The Model option performs the operation over all the geometrical entities in the model.

Uncollapse

Menu: Geometry->Edit->Uncollapse

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.

Intersection

Menu: Geometry->Edit->Intersection

Using this option, the intersection of many geometrical entities can be performed.

Intersection: Line-line

With the command Intersect lines, two lines must be selected. GiD then searches for the closest points between the two lines. If the two lines already touch, a new point will be created where they cross.

If the lines do not intersect, GiD determines the point where the two lines are the closest, it draws both points and asks for confirmation. If confirmed, the new point on the line selected second is moved to the new point on the line selected first, creating a unique point. In the case of an arc and a straight line, for example, this effectively creates four lines out of two, but with two straight lines, where an endpoint is highlighted, GiD simply extends the second line until it reaches the first.

The 'No Divide Lines' option creates the intersection point, i.e. draws the points where the lines are closest, but does not modify the lines.

Note: Polylines cannot accept this option.

Caution: The second selected line can only have higher entities if it is not necessary to extend this line.

Intersection: Multiple lines

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.

Intersection: Surface-2 points

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.

Note: See Point in line , Point in surface which can be used to define the points.

Intersection: Surface-lines

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.

Intersection: Surface-surface

This command creates the intersection lines between two surfaces. If these lines intersect surface contour lines, they are divided.

The 'No Divide Lines' option creates the intersection point but does not modify the contour lines.

By default the surfaces are divided, unless the No divide surface option is selected.

Intersection: Multiple surfaces

This command creates the intersection lines between surfaces.

Surface boolean operations

Menu: Geometry->Edit->Surface boolean op.

You need to select two 2D surfaces located in the XY plane (order is important when dealing with subtraction).

The valid surface boolean operations are:

Volume boolean operations

Menu: Geometry->Edit->Volume boolean op.

The GiD Volume Boolean Modeler has been designed to accomplish geometric feats such as physically punching a hole through a volume, combining two volumes into one, and creating a new volume from the intersecting points of two separate volumes.

The valid volume boolean operations are:

Two volumes must be selected (order is important when dealing with subtraction).