8

638 Chapter 8: Modifiers
Edit Geom e try rollout
Repeat Last—Repeats the most recently used
command.
Forexample,ifyouextrudeavertex,andwantto
apply the same extrusion to several others, select
the others, and then click Repeat Last.
Note: Repeat Last does not repeat all operations.
For instance, it does not repeat transforms. To
determine which command will repeat when you
click the button, check the button’s tooltip. If no
tooltip appears, nothing will happen when you
click the button.
Constra ints—Lets you use existing geometry to
constrain sub-object transformation. Use the
drop-down list to choose the constraint type:
•
None—No constraints.
•
Edge—Constrains vertex transformations to
follow edges.
•
Face—Constrains vertex transformations to
face surfaces.
With Constraints set to Edge, moving a vertex slides it
along an existing edge, depending on the direction of the
transformation. If set to Face, the vertex moves only on the
polygon’s surface.
Note: The C onstraints setting persists at all
sub-object levels.
Preserv e U V s—When on, you can edit vertices
without affecting the object’s UV mapping. You
can choose which mapping channels to preserve;
see Preserve UVs Settings, following. Default=off.
W ithout Preserve UVs, there is always a direct
correspondence between an object’s geometry and
its UV mapping. If you map an object, and then
move vertices, the texture moves along with the
sub-objects, whether you want it to or not. If you
turn on Preserve UVs, you can perform minor
editing t asks without changing the mapping.
Tip: For b est results w ith Preserve UVs, use it for
limited vertex editing. For example, you’ll usually
have no trouble moving a vertex within edge or
face constraints. Also, it’s better to perform one
big move than several smaller moves, as multiple
small moves can begin to distort the mapping. If,
however, you need to perform extensive geometry
editing while preserving mapping, use the
Channel
Info utility (page 2–1549)
instead.