8

992 Chapter 9: Surface Modeling
Split M esh—
Affectstheseamsofdisplacedmesh
objects; also affects texture mapping. When on,
themeshissplitintoindividualfacesbeforeitis
displaced; this helps preserve texture m apping.
When off, the mesh is not split and an internal
method is used to assign texture mapping.
Default=on.
Tip: This parameter is require d because of an
architectural limitation in the way displacement
mapping works. Tur ning Split Mesh on is usually
the better technique, but it can cause problems for
objects with clearly distinct faces, such as boxes,
or even spheres. A box’s sides might separ ate as
they displace outward, leav ing gaps. And a sphere
might split along its longitudinal edge (found in
the rear for spheres created in the Top v iew) unless
you turn off Split Mesh. However, texture mapping
works unpredictably w hen Split Mesh is off, so
you might need to add a
Displace Mesh modifier
(page 1–499)
and make a snapshot (page 1–438)
of the mesh. You would then apply a UVW Map
modifier (page 1–905)
andthenreassignmapping
coordinates to the displaced snapshot mesh.
Subdivision Presets group & Subdivisio n
Method group
Thecontrolsinthesetwogroupboxesspecifyhow
the displacement map is applied when Subdivision
Displacement is on. They are identical to the
Surface Approximation controls (page 1–1241)
used for NUR BS surfaces.
Editable Mesh (Ver tex )
Select an editable mesh object. > Modify panel >
Selec tion rollout > Vertex
Selec t an editable mesh obje ct. > Modify p ane l > M odifier
Stack display > Expand Editable Mesh. > Vertex
Select an editable m esh object. > Quad menu > Tools
1quadrant>Vertex
Vertices are points in space: they define the
structure of faces. When vertices are moved or
edited, the faces they form are affected as well.
Vertices can also exist independently; such isolated
vertices can be used to construct faces but are
otherwise invisible when rendering.
At the Editable Mesh (Vertex) sub- object level, you
can select single and multiple vertices and move
them using standard methods. This topic covers
the Edit Geometry rollout; for other controls, see
Editable Mesh (page 1–984) .
Procedures
To weld mesh vertices:
You can use either of two methods to combine
several vertices into one, also known as welding. If
the vertices are very close together, use the Weld
function. You can also use Weld to combine a
number of vertices to the average position of all
of them.
Alternatively, to combine two vertices that are far
apart, resulting in a single vertex that’s in the same
position as one of them, use Target Weld.
Tip: Weldingverticesisconsiderablyeasierwith
poly objects. See this procedure:
To weld polygon
ver tices: (p age 1–1026)
1. To u s e We l d :
1. On the S elec tion rollout, turn on Ignore
Backfacing, if necessary. This ensures that
you’reweldingonlyverticesyoucansee.
2. Select the vertices to weld.