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1026 Chapter 9: Surface Modeling
Vertex—Turns on Vertex sub-object level,
which lets you select a vertex beneath the cursor;
region selection selects vertices within the region.
Edge—Turns on Edge sub-objec t le vel, which
lets you select a polygon edge b eneath the cursor;
region selection selects multiple edges within the
region.
Border—Tur ns on Border sub-object level,
which lets you select a sequence of edges that
borders a hole in the mesh. Borders are always
composed of edges with faces on only one side of
them,andarealwayscompleteloops.Forexample,
a box doesn’t have a border, but the teapot object
has a couple of them: on the lid, on the body, on
the sp out, and two on the handle. If you create
a c ylinder, then delete one end, the row of edges
around that end forms a border.
When Border sub-object level is active, you can’t
select edges that aren’t on borders. Clicking a
single edge on a border selects that whole border.
You c an cap a borders, either in Editable Poly or by
applying the Cap Holes modifier (page 1–569).You
can also connect borders between objects with the
Connect compound object (page 1–328).
Polygon—Turns on Polygon sub-object level,
which lets you select polygons beneath the cursor.
Region selection selects multiple polygons within
the region.
Element—Turns on Element sub-object level,
which lets you select all contiguous polygons in an
object. Region selection lets you select multiple
elements.
By Vertex—When on, you can select sub-objects
only by selecting a vertex that they use. When you
click a vertex, all sub-objects that use the selected
vertex are selected.
Ignore Ba ckfaci ng—When on, selection of
sub-objects affects only those facing you. When
off (the default), you can select any sub-object(s)
under t he mouse cursor, regardless of their
visibility or facing. If there are more than one
sub-object under the cursor, repeated clicking
cyclesthroughthem. Likewise,withIgnore
Backfacing off, region selection includes all
sub-objects, regardless of the direction they face.
Note: ThestateoftheBackfaceCullsettinginthe
Display panel does not affect sub-object selection.
Thus, if Ignore Backfacing is off, you can still select
sub-objects, even if you can’t see them.
By Angle—When on and you select a polygon,
the software also selects neighboring polygons
basedontheanglesettingtotherightofthecheck
box. This value determ ines the maximum angle
between neighboring polygons to select. Available
only at the Polygon sub-object level.
For example, if you click a side of a box and the
angle value is less than 90.0, only that side is
selected, bec ause all sides are at 90-degree angles
to each other. But if the angle value is 90.0 or
greater, a l l sides of the box are selected. This
function speeds up selection of contiguous areas
made up of polygons that are at similar angles to
one another. You can select coplanar polygons
with a single click at any angle value.
Shrink—Reduces the sub-object selection area
by deselecting the outermost sub-objects. If
the s election size can no longer be reduced, the
remaining sub-objects are deselected.
Grow—Expands the selection area outward in all
available directions.
Forthisfunction,aborderisconsideredtobean
edge selection.