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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.
- 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.
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- Num divisions: The line or surface will be converted into equally spaced pieces. In the case of surfaces it is necessary to give the division direction as u or v.
- Near point: With this option one point must be selected near the line or the surface. Points inside the entities can be selected (see Point in line, or Point in surface). The line or the surface will be divided into two entities near that point. In the case of surfaces it is necessary to give the division direction as u or v.
- Parameter: One factor is given between 0.0 and 1.0 and the entity will be divided where the parametric variable takes that value. In the case of surfaces it is necessary to give the division direction as u or v.
- Relative length: (lines only) One factor is given between 0.0 and 1.0 to divide the line with relative arc length ratio equal to the selected factor. (Same concept as Parameter if the curve was arc length parameterized).
- Length: (lines only) The length of the resulting divided lines is given, and GiD divides the line into as many lines as it can. If the length given is bigger than the length of the selected line, no division is made.
- Split: (surfaces or volumes) The surface/volume will be divided following the divide lines/surfaces. These lines/surfaces must share points/lines with the to be splitted (Command: Geometry Edit SplitSurf/SplitVolume ).
Note: After the division, the old entity disappears and the new entities are created.
Geometry Menu>Edit>Join
Menu: Geometry->Edit->Join
With this option you try to join connected entities.
Join lines:
To join the lines of a selection that are connected with 'similar tangent' (with an user tolerance).
Note: the lines are not joined if the connection point belongs to other lines, has some condition applied, or the lines have set an structured number of divisions.
Join surfaces:
- Rebuild by boundary:
A group or connected surfaces must be selected in order to try to create a single approximated surface.
- QuickJoin (default option)
- NoQuickJoin. More parameters are available.
- IsProjectable : Yes or Not
- WeightBoundary: Yes or Not
- NumApproxPoints
- Tolerance
- Join only coplanars:
A group of surfaces must be selected, and automatically are detected subgroups of planar parts that are joined in single planar surfaces.
- TolAngle could be set to determine when two surfaces are coplanar
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- Use points: When meshing this polyline, there will be at least one node at every point location that defines the polyline. These will be the endpoints of interior lines.
- Not use points: When meshing this polyline, the mesh generator ignores the points and therefore the nodes will be placed anywhere. This is the default option. Nodes will only be put in the position of a point if there is a 4-sided surface over a part of a polyline (see Automatic 4-sided surface creation).
- Only points: When meshing this polyline, the nodes will only be placed where the geometry points are.
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.
Geometry Menu>Edit>SurfMesh
Menu: Geometry->Edit->SurfMesh
Select one or several surface meshes (see Surface mesh). The options are:
- Draw mesh: Surface will be drawn as a mesh.
- No draw mesh: Surface will be drawn as a regular surface with magenta lines close to the boundary lines.
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- Fix boundary Check the fix boundary option if you do not want to move the boundary control points of the line.
- Insert knot: You are asked for a knot value between 0.0 and 1.0 and this is then inserted. The program checks that the knot multiplicity is not greater than the order (order=degree+1). As the number of knots increases, the number of control points also increases, so this option can be used to have more points defining the same curve.
- Knot removal : the inverse of knot insertion. Remove knots if possible without change shape with a given tolerance. (interesting to save memory)
- Elevate degree: With this option the degree of the curve is raised by one. The new curve will have the same shape but with more control points and knots.
- Reduce degree : the inverse of degree elevation. Decrease the polynomial degree if possible without change shape with a given tolerance.
- Change weight: A new positive weight can be introduced for any control point, with the exception of the end points.
- Cancel weights: All weights of the NURBS are converted to 1.0 and the curve is no longer rational.
- Reparameterize: With the same control points a new curve is calculated to get a better curve with a more uniform parameterization.
- Similar cubic: This option converts the curve to a simplified one with degree=3, which is only an approximation of the original one.
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- Insert knot: You are asked for a knot value between 0.0 and 1.0 and it is then inserted. The program checks that the knot multiplicity is not greater than the order. This option can be used to have more points defining the same surface.
- knot removal: the inverse of knot insertion. Remove knots if possible without change shape with a given tolerance. (interesting to save memory)
- Elevate degree: With this option the degree of the surface is raised by one. The new surface will have the same shape but with more control points and knots.
- Reduce degree : the inverse of degree elevation. Decrease the polynomial degree if possible without change shape with a given tolerance.
- Change Weight: A new positive weight can be introduced for any control point, with the exception of the end points that must have weight=1 (to force the surface to pass over the corner control points).
- Cancel weights: This converts the weights of all the control points to 1.0
- Reparametrize: This reparameterizes the surface obtaining an optimized surface. When a Nurbs surface is not well parameterized, the mesh is of a lower quality.
- Similar cubic: This option converts the surface to a simplified one with degree=3 in both parametric directions, which is only an approximation of the original one.
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- With lines:
With this option you can select one existing NURBS or planar surface and a set of closed lines that are inside it and that form one or more holes. The lines may be created by an intersection with another surface. The holes will be added to the existing surface.
- With surfaces:
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- 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.
- 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.
- 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.
- Surfaces: This command creates the intersection lines between several surfaces.
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- Union: Fuses two surfaces wherever they intersect to create a single, more complex surface.
- Intersection: Creates a surface based on the intersecting points of two separate surfaces.
- Subtraction: Negates a specific portion of a surface to create a hole or indentation.
- Subtraction and intersection: Creates the intersected and the substracted surface at the same time.
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- 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.
- Subtraction and intersection: Creates the intersected and the substracted volume at the same time.
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