9

636 Chapter 8: Modifiers
this makes it easy to see the seams b etween the
broken pieces. To fix this, the artist selects all
the pieces of the breaking object and applies the
Edit Nor mal modifier to all of them at once.
She then selects the normals across the seam
and u nifies them s o they are pointing in the
same di rection. The artist then exports to the
game engine.
Usa ge Notes
Please observe the following notes and precautions
when using the Edit Normals modifier:
• Edit Normals supports both poly objects
(polygon-based) and mesh objects
(triang le-based). If you apply Edit Normals to
a poly object, the result is a poly object. If you
apply Edit normals to any other object type, the
result is a mesh object.
• Edit Normals also supports embedding of
edited-normal data when collapsing the stack,
and w hen conver ting from poly object to mesh
object, but not when converting fr o m a mesh
object to any other object type. If you apply
Edit Normals to a primitive object, adjust
the normals, and then collapse the stack (or
convert to Editable Mesh), the software embeds
any changes to the normals in the mesh object,
including selection status. Primitive objects are
mesh-based, so if you convert the same object
to Editable Poly, the edited normals are lost.
On the other hand, if you convert a pr imitive
object to Editable Poly, apply Edit Normals,
adjust the normals, and then collapse the stack,
resulting i n a poly object, the normals are
retained. You can subsequently regain access to
embedded, edited normals in a collapsed object
by applying another Edit Normals modifier.
• Any mo difiers that change topology will remove
changes applied to the norma ls with the Edit
Normals modifier. These include MeshSmooth,
Tessellate, Slice, Mirror, Symmetry, Face
Extrude, and Vertex Weld. Oddly enough, it
also means that the Normal modifier (used
to flip face orientations) will not support the
edited normals. Since Tur n To Poly can be used
to modify face topology, it also strips off the
edited norm als.
• All compound objects strip off the edited
normals from their operands.
• The good news: All deformation and map
modifiers preserve the normals. For instance, if
you apply a Bend, the normals should be bent
along with the geometry. Map modifiers, such
asUnwrapUVW,won’taffectthenormalsatall.
• However, a few geometric modifiers do not
fully support the new normals. They won’t
strip them away, but neither will they correctly
deform any explicit normals. Modifiers in this
category include Push and Relax.
• The Smooth modifier correctly modifies any
non-specified normals, while leaving the
specified and explicit normals alone.
• Like Mesh Select and Poly Select, Edit Normals
“inherits” attributes from below it in the stack.
Forexample,ifyoucreateabox,applyanEdit
Normals modifier, change some normals, and
then apply a second Edit Normals modifier, the
top Edit Normals "inher it" the user-specified
normals from the pipeline, just as Mesh Select
adoptsthecurrentselectionwhenyouapply
it. But the top Edit Normals modifier ignores
any subsequent changes to the original Edit
Normals modifier, just as Mesh Select ignores
any changes made to the s election below it in
the stack after it is applied.