Global Topology Palette

Glue button

You can make objects topologically the same by picking either two points or two curves and selecting the Glue button. Surfaces and vectors cannot be glued. If no objects are picked, all visible objects are glued using the specified tolerance. When two objects are glued, the respective objects are then considered to be topologically adjacent. For example: If you glue two curves that are each connected to two different surfaces, these two surfaces are now considered to be topologically adjacent. CAUTION: If you pick two curves of significantly different lengths, there may be serious problems generating a quality surface grid.

Tolerance

You can set the tolerance, which is the maximum distance which entities can have between them to be considered the same entity, by using the Tolerance field. If you are unsure of the value that would suit your project best, you can glue a couple of entities separately (like two curves or two points), and see what the maximum distance is between them; it will be listed in the message field. If the distance is about the same in each example checked, the tolerance can be set to a number just slightly higher than this given distance.

Unglue button

You can unglue by picking any number of curves and surfaces and selecting the Unglue button. A message will appear telling you the number of curves and surfaces unglued. If an edge that is not shared by a surface is unglued, the result will be that the endpoints of the curve are unglued from adjacent curves. If the edge is shared by adjacent faces, each adjacent face will be unglued at the specified edge. If a face is picked, all of the edges of the face will be unglued from adjacent faces. The curves created by ungluing one face from another will still appear to be one curve (they will be drawn on top of each other).

Trim

Creates a trimmed surface(s) from the surface(s) selected.  A surface can be trimmed only when it has a set of parametric curves that form topologically valid (non-intersecting) loops. See curves for how to build parametric curves. If the surface has bounding parametric curves and another topologically valid loop on the inner area, the center of the surface will be trimmed out of the inner loop. If the surface only has one topologically valid loop, the surface around the loop will be trimmed from the surface. If a trimmed surface is picked and Delete is pushed, the trimmed surface will return untrimmed.  For more information on trimming see the trimming tutorials.

Check topology button

Before creating any grids, the model must be topologically valid. A 3-D geometry is topologically valid if and only if all curves have exactly two surfaces topologically adjacent to them. The Check topology button checks the model for topological validity. The check picks all objects that are topologically invalid.

Force topology check toggle

With this toggle turned on, all edges are included in the topology check. By default, edges that are attached to a surface with a transparent bc applied are not included in the topology check.

Degenerate topology button

You can pick degenerate curves (entire curve is within the same point tolerance) and degenerate surfaces (at least one computational direction is entirely within the same point tolerance) by selecting the Degenerate topology button.

Display Resolution

You have the ability to change the display resolution of a given curve or surface by using the Resolution button. The display resolution determines the accuracy of projecting curves onto surfaces as well as curve-curve, curve-surface and surface-surface intersections. To change the display resolution of a curve, put the desired resolution in the U field and hit the Resolution button. To change the display resolution of a surface change both the U and V fields and hit the Resolution button. NOTE: U and V represent the computational parametric directions of the given curve or surface.

Calculate resolution toggle

You have the ability to calculate the display resolution of a curve or surface by highlighting the Calculate resolution toggle. The resolution is calculated by multiplying the number of control points by the order of the curve. CAUTION: Calculating the resolution of a curve may produce thousands of segments and should be used sparingly.

For help in this area, please see the Topology Tutorial.