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1056 Chapter 9: Surface Modeling
Preserv e UVs —
When on, you can edit sub-objects
without affecting the object’s UV mapping. You
can choose any of an object’s mapping channels
to preserve or not; see Preser ve UVs Settings,
following. D efault=off.
Without Preserve UVs, there is always a direct
correspondence b etween an object’s geometr y
and its UV mapping. For example, if you map an
objectandthenmovevertices,thetexturemoves
along with the sub-objects, whether you wa nt it
toornot.IfyouturnonPreserveUVs,youcan
perform minor editing tasks without changing
the mapping.
Tip: For best results with Preserve UVs at the
vertex level, use it for limited vertex editing. For
example, you’ll usually have no trouble m oving
avertexwithinedgeorfaceconstraints. Also,
it’s better to perform one big move than several
smallermoves,asmultiplesmallmovescanbegin
to distor t the mapping. If, however, you need
to perform extensive geometry editing while
preserving mapping, use the Channel Info utility
(page 2–1738) instead.
Original object (left); Scaled vertices with Preserve UVs off
(center); Scaled vertices w ith Preser ve UVs on (right)
Pres er v e UV s Set tings —Opens the Preserve Map
Channels dialog (page 1–1075),whichletsyou
specify which vertex color channels and/or texture
channels (map channels) to preserve. By default,
all vertex color channels are off (not preserved),
andalltexturechannelsareon(preserved).
Cr e ate —Lets you create new geometry. How this
button behaves depends on which level is active.
•
Object, Polygon, a nd Element levels —Lets you
create polygons from isolated vert ices and
border vertices. All vertices in the object are
highlighted. Click three or more existing
vertices in succession to define the shape of the
new polygon. (The cursor changes to a cross
when it is over a vertex that can legally be part
of the polygon.) To finish polygon creation,
double-click the last vertex. You can also finish
creating the polygon by clicking any vertex
of the new polygon a second time. You can
also create new polygons at the Polygon and
Element sub-object levels.
Youcanaddverticesinthismodeby
Shi f t +clickinginanemptyspace;these
vertices are incorporated into the polygon
you’re creating.
Youcanstartcreatingpolygonsinanyviewport,
but all subsequent clicks must take place in the
same viewpor t.
Tip: For best results, click vertices in
counterclockwise (preferred) or clockwise
order . If you use clockwise order, the new
polygon will face away from you.
•
Vertex level—Lets you add vert ices to a single
selected p oly object. After selecting the object
and clicking Create, click anywhere in space
to add free-floating (isolated) vertices to the
object. The new vertices are placed on the active
construction plane unless object snapping is
on. For example, with face snapping on, you
can create vertices on object faces.
•
Edge and B order levels—Lets you create an edge
betweenapairofnon-adjacentverticesonthe
same polygon. Click Create, click a vertex,
and then move the mouse. A rubber-band line
extends from the vertex to the mouse cursor.
Click a second, non-adjacent vertex on the
same polygon to connect them with an edge.
Repeat,or,toexit,right-clickintheviewport
or click Create again.
Edges you create separate the polygons.
For example, by creating an edge inside a
quadrilateral polygon, you turn it into two
triangles.