9

1000 Chapter 9: Surface Modeling
Inter face
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 the edge of a face or p olygon beneath
the cursor; region selection selects multiple edges
withintheregion.AttheEdgesub-objectlevel,
selected hidden edges are displayed as dashed
lines, allowi ng for more precise select ion.
Face —Turns on Face sub-object level, which
lets you select a triangular face beneath the cursor;
region selection selects multiple triangular faces
within the region. If a selec ted face has a hidden
edge and Shade Selected Faces isoff,theedgeis
displayed as a dashed line.
Polygon—Turns on Polygon sub-object level,
which lets you select all coplanar faces (defined by
the value in the Planar Threshold spinner) b eneath
the cursor. Usually, a polygon is the area you see
within the visible wire edges. Region selection
selectsmultiplepolygonswithintheregion.
Element—Turns on Element sub-object level,
which lets you select all contiguous faces in an
object. Reg ion selection lets you sele ct multiple
elements.
By Vertex—When on, and you click a vertex, any
sub-objects (at the current level) that use that
ver tex are selected. Also works with Region Select.
Note: When By Vertex is on, you can select
sub-objectsonlybyclickingavertex,orbyregion.
Ignore Ba ckfaci ng—When on, selection of
sub-objects selects only those sub-objects whose
normals are visible in the viewport. When off
(the default), selec tion includes all sub-objects,
regardless of the direction of their normals.
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.
Ignore V isible Edges—This is enabled when the
Polygon face selection method is chosen. When
Ignore Visible Edges is off (the default), and you
click a face, the selection will not go beyond the
vi sible edges no matter what the setting of the
Planar Thresh spinner. When this is on, face
selection ignores the visible edges, using the Planar
Threshsettingasaguide.
Generally, if you want to select a "facet" (a coplanar
collection of faces), you set the Planar Threshold
to 1.0. On the other hand, if you’re trying to select
a c urved surface, i ncrease the value depending on
the amount of curvature.
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Planar Thresh—(Planar Threshold) Specifies the
threshold value that determ ines which faces are
coplanar for Polygon face selec tion.