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Projection Modifier 769
Pick Original—
Click this, and then select an
unmodified copy of the current object. You
should pick an object with the same topology as
the current object, which has the same number
of vertices. While you can select a completely
different object w ith equal vertices, the results are
unpredictable.
Iterations—Specifies the number of calculations
toward the solut ion. The higher this number, the
closer the object comes to matching the original
object and the slower the process. When this is set
to zero, the original object has no effect, as if the
Preserve modifier were never applied.
Preservation Weights group
Edge Lengths, Face Angles, V olumes—Adjusts the
relative importance of the three components you’re
attem pting to preserve: edge lengths, face angles,
and volume. In most cases, you’d leave these at
their default settings, but you can achieve some
interesting effects by altering them. Higher face
angles, for example, produce st iffer meshes.
Selection group
Provides options that let you specify which
selection level to take from previous select ion
modifiers in the st ack. The Preserve modifier acts
on the specified selection.
Apply to Whole Mesh—Applies Preserve to the
entire object, regardless of the selection passed
from previous levels of the stack. Disables the
other two check boxes.
Selected Verts Only—Uses previous sub-object
vertexselections. Notethatitdoesn’tmatterif
the Vertex sub-object level is act ive in a previous
stack item. As long as vertices have been selected,
Preserve will use that selection.
Inver t S election—Inverts the selection passed up
the stack.
Note: If al l of the check boxes are turned off,
Preserve uses w hatever active selection is passed
up the stack. Thus, if a Mesh Select modifier is
set to t he Vertex level, then that vertex selection is
used. If the same Mesh Select modifier is set to t he
top (object) level, then the entire object is affected.
Pr oj ect ion M odif i er
Select an object. > Modify panel > Modifier List >
Object-Space Modifiers > Projection
The Projection modifier is used primarily to
manage objects for producing normal bump maps
(page 3–150). You apply it to the low-resolution
object, and then pick a high-resolution object as
thesourcefortheprojectednormals.Whenyou
use the Render To Texture dialog (page 3–156) to
s e t u p proj e c t i o n , R e n der To Te x t u r e a pplies t he
Project ion modifier to the low-resolution object
aut omatically. You can also explicitly apply the
Projection modifier to set up the projection before
you use Render To Texture.
Note: The low-resolution object requires UV
coordinates, but the high-resolution source object
does not need to have them. When the normals
mapisrendered,youcanchoosetohaveRender
To Te x t u re a p ply a n “Automatic Flatten UVs”
(Unw rap UVW) modifier (page 1–878) to the top of
the low-res object’s stack; or you can use existing
mapping, if such exists.
You can apply more t han one instance of the
Projection modifier to the same object, and you
can instance it across multiple o bjects.
The Projection modifier is a topology-dependent
modifier (page 3–1023),sowhenyouselectan
item in the stack that is lower than the Projection
modifier,youseeawarningdialogthatasksif