Collapse Edges
The operation collapses an edge by removing it, merging its adjacent vertices to one, and reconnecting the adjacent edges to the merged vertex. Which vertex to keep is determined by geometrical criteria, but is typically the one with the most ingoing edges. All edges in the geometry must have distinct start and end points. The software will ensure this by not collapsing an edge if that would introduce edges that fail to meet the requirement.
Figure 7-15: A short edge, highlighted in blue, which is collapsed into the vertex to the right, where four edges are connected.
For more control over which vertex to keep, refer to Merge Vertices. An alternative is to use the Ignore Vertices operation. The Remove Details operation provides a fully automated way to find and remove short edges within the whole geometry or a selection of entities.
To use the operation, in the Geometry toolbar, from the Virtual Operations menu (), select Collapse Edges (). Then enter the properties of the operation using the following sections:
Input
Select the edges that you want to collapse in the Graphics window. These then appear in the Edges to collapse list. If the geometry sequence includes user-defined selections above the Collapse Edges node, choose Manual to select edges, or choose one of the selection nodes from the list next to Edges to collapse.
Click the Active button to toggle between turning ON and OFF the Edges to collapse selections.
Select the Ignore merged vertices check box to ignore the resulting merged vertices. A vertex can be ignored if there are exactly two edges connected to the it.
Figure 7-16: Two edges, highlighted in blue, to be collapsed. Leaving the Ignore merged vertices check box selected will ensure that resulting vertices are ignored (indicated by top arrow in upper right image). However, if there are more than two ingoing edges, the vertex will always be kept (bottom arrow in upper right image). If the Ignore merged vertices is cleared, all vertices are kept after the operation is built (indicated with arrow in the bottom right image).