The operation is subject to the following restrictions: GAMBIT does not allow you to delete vertices that constitute parts of higher-topology entities. Stage Before After Domain Foreground Background Foreground Background Vertices vertex.1 vertex.2 vertex.3 vertex.4 None vertex.1 vertex.4 v_vertex.5 vertex.2 vertex.3 Edges edge.1 edge.2 None v_edge.3 v_edge.4 edge.1 edge.2 Connecting Edges As Data Formats Software Libraries Numerical Software Parallel Computing General Sites Software Fluid Dynamics Mesh Generation Visualization Commercial CFD Codes Hardware Benchmarks News and Reviews Hardware Vendors Clusters GPGPU Misc References Validation It includes the following options.

Figure 2-138 shows the results of a perpendicular draft sweep operation involving a profile and path identical to those shown in Figure 2-132(a). Preserve first vertex location creates the new vertex at the location of the first vertex listed in the Vertices list. The curves that define the edges are not coincident with the surface of the face at its boundaries. The draft angle represents the extent to which the profile is expanded or contracted as it is swept along the path.

For instructions on using the Vector Definition form, see "Using the Vector Definition Form" in Section 2.1.4. Therefore, the existence of v_edge.7 in the foreground of the model GAMBIT imposes fewer overall constraints on mesh node placement than are imposed by the existence of edge.1 and edge.2. T-Connecting Lone Edges As an example of a T-connect operation, consider the topological configuration shown in Figure A-23. The Create Vertices at Edge Intersections command requires the following input parameters: Two edges that define the points at which the vertices are to be created Tolerance value (optional) Vertex geometry

Figure 2-146: Effect of direction option on brick position Using the Create Real Brick Form To open the Create Real Brick form (see below), click the Create Real Brick command button Figure 2-152: Torus radius specifications Specifying the Axis of the Torus To orient the torus in the model domain, you must specify the coordinate axis that constitutes the central axis of Regardless of whether you specify the volume by means of the Volume list box or by means of the mouse, GAMBIT locates the vertex creation point in the center of the Height specifies the dimension of the brick in the z direction.

Figure A-8: Curved, four-sided face with parasite virtual vertices If you perform a virtual construct operation to create a virtual edge that employs v_vertex.5 and v_vertex.6 as its endpoints and face.1 For example, if you locate the creation point at the exact center of the edge, the value of u is 0.5. Using the Create Real Torus Form To open the Create Real Torus form (see below), click the Create Real Torus command button on the Geometry/Volume subpad. Figure A-10: Repositioned parasite vertex and edge For a description of the procedures and specifications required to modify the position of a virtual vertex, see "Slide Virtual Vertex" in Chapter 2

Figure 2-141: Twist-method face-sweep operation, 180° twist angle By default, GAMBIT moves the path (twist axis) to the nearest point on the profile face before sweeping the face to create the Figure A-12: Merging of two real faces If you merge face.1 with face.2, GAMBIT replaces them in the model foreground with a single virtual face, v_face.3 (see Figure A-12(b)). The faces face.1 and face.2 are connected to each other by means of their common edge, edge.7, and face.2 and face.3 are connected to each other by means of edge.8. For example, consider the five-sided, planar face shown in Figure A-14(a).

Operation Description Collapse Splits a face and merges the resulting pieces with two or more neighboring faces. The operation requires the following input specifications: One or more vertices (real or non-real) to be projected onto an existing edge The target edge (real or non-real) onto which the vertices If you specify position parameters or coordinates that do not lie on the host entity, GAMBIT "snaps" the vertex to the location on the entity that is nearest the specified coordinates. Operations Characteristics Real Boolean Alter the underlying topology of the model Often involve complex calculations Virtual split Do not affect the underlying structure of the model Are not computationally intensive In

The types of edges (real or non-real) used to define the points of intersection do not affect the types of vertices that result from the vertex creation operation (see below). Using the Create Real Sphere Form To open the Create Real Sphere form (see below), click the Create Real Sphere command button on the Geometry/Volume subpad. Specifying the With mesh Option If you sweep a meshed face, GAMBIT allows you to project the face mesh during the sweep operation, thereby creating a meshed volume. Specifying the Path The sweep path can be defined by means of either an edge or a vector.

GAMBIT provides two Tolerance options: Auto Manual The purpose of the Tolerance option depends, in part, on the type of volume created by means of the face-stitch operation (see above). A.3.2 Virtual Entity Categories There are two general categories into which entities that participate in GAMBIT virtual geometry operations can be grouped: Relationship Class The relationship category defines which specific real Label specifies that labels corresponding to highlighted vertex names are displayed in the graphics window. Specifying the Cylinder Radii To define the cross section of the cylinder, you must specify its major and minor axes.

Figure 2-139: Perpendicular draft face sweep—effect of draft angle The Effect of Draft Type When you sweep a face by means of the perpendicular draft method and expand the profile by By default, Radius 1 is aligned with the x axis, and Radius 2 is aligned with the y axis. To create real vertices, deselect the Virtual option. Angle specifies the draft angle.

For examples of the types of entities that result from GAMBIT virtual construct operations, see "Parasite Entities" and "Orphan Entities" in Section A.2, above. To connect vertices, you must specify the following parameters: Two or more vertices to be connected The connection type Specifying the Vertices to Be Connected The vertices to be connected can Highlight shortest edge highlights the shortest edge that exists in the current model. Specifying the Volume Type The Stitch Faces command can be used to form real and/or virtual volumes.

All six edges and vertices exist in the foreground of the model. The Create Real Frustum form includes the following specifications. It is then possible to mesh the overall geometry of the original faces by means of a single meshing operation. If you perform a virtual split operation, GAMBIT replaces the real entity in the model foreground with two virtual entities and shifts the original real entity to the model background.

The configuration shown in Figure 2-130(b) is not valid because the normal to the face (ABC) is perpendicular to the path at its starting point (D). specifies the reference coordinate system. In Figure 2-148(a), each prism possesses an odd number of sides. If you select the Retain option, GAMBIT retains the original volumes when it performs the Boolean operation.

A.4.1 Low-Level Operations GAMBIT provides the following types of low-level virtual operations.