Modeling 1: Polygons - An Introduction to Computer Graphics for Artists - page 76

Fig. 6.6 Four tools that delete points: ( 1 ) delete, ( 2 ) collapse, ( 3 ) cut, ( 4 ) bevel

6.3.3.1 Delete

A true “delete” command will only delete the selected vertex or vertices without
affecting surrounding vertices or edges. Some will delete the vertex and all con-
nected edges, some will only delete the vertex if it is isolated. Some applications
have a “delete” command that works like a “collapse” function (described below).
These are different tools, so be careful that you know which one you are using.

6.3.3.2 Collapse

The collapse function deletes the selected component/components, and fi lls the
resulting space by averaging the position of nearby vertices. The effect is of a heavy
weight dropped on the apex of a tent. It pulls everything towards the weight. This
tool is helpful when derezing an object, but if you don't want neighboring structures
to be affected, use delete instead.

6.3.3.3 Weld/Merge

Unlike other commands, this one has several different names from application to
application, but they all do the same thing: it checks for the selected component type
within a certain radius of the selection and then averages the distance between any-
thing found in that radius with the selected component and collapses the elements
together. This is a good way to eliminate nearly invisible vertices and faces that are
so close together you'd never fi nd them without this command.

6.3.4 Booleans

A Boolean operation is when two or more objects are evaluated for intersection, and
then a new polyset is created based on the intersection (Fig. 6.7 ). This can result in
adding or deleting vertices from a model, and is sometimes the best way to create