9

988 Chapter 9: Surface Modelin g
Original patch with edges selec ted (top) and three-sided
patches added (bottom)
Add Tri adds a three-sided patch to each selected
edge. Select one or more edges, then click Add Tri
to add the patch or patches.
Add Quad adds a four-sided p atch to each selected
edge. Select one or more edges, and then click Add
Quad to add the patch or patches.
Create ( V er tex , Patch, and Element lev els only )—Lets
you add geometry to the patch object. Available at
Vertex, Patch, and Element sub-object levels only.
At the Vertex sub-objec t level, turn on Create and
then click anywhere to add vertices to the object.
At the Patch and Element levels, y ou can add
three- and four-sided p atches. The cursor changes
to white cross hairs when over an existing patch
vertex. Select an ex isting vertex by clicking it.
Click in free space to create a new vertex at that
location;thisvertexisincludedinthesequenceof
vertices for the new patch.
• To create a Tri Patch:Clickthreetimesin
free space or on existing vertices. Right-click
anywhere, or left-click one of the vertices in the
current sequence to complete the creation of a
Tri Patch.
• To create a Quad Patch:Clickfourtimesinfree
space or on existing vert ices. The Quad Patch is
automatically created at the fourth click.
No operation takes place if you right-click or select
a vertex in the current sequence with only one or
two vertices in the sequence.
Detach (Patch and Element levels only)—Lets you
select one or more patches or elements within the
current object and then detach them (or copy
them) to form a separate patch object.
•
Reorient—When on, the detached patch or
element copies the position and orientation
of the source object’s Local coordinate system
(when the source object was created). The new
detached object is moved and rotated so that
its L ocal coordinate system is positioned and
aligned w ith the origin of the current ac tive
grid.
•
Co py—When on, the detached patches or
elements are copied to a new patch object,
leaving the origina ls intact.
Attach—Lets you attach an object to the currently
selected patch object. Click t he object you want to
attach to the currently selected patch object.
If you attach a non-p atch object, the object is
converted to a patch object.