8

Geometric Primitives 163
• Turn on the Smooth check box on the
Parameters rollout of a parametric object to set
default smoothing for the object.
•
Turn on the Auto Smooth check box on
the Rendering rollout of a spline shape to turn
on smoothing.
•Applya
Smooth mo difier (page 1–818) .Ifa
Face sub-object selection is active, Smooth
applies to the selected faces. If no faces are
selected, Smooth applies to the entire object.
•Applyan
Edit Mesh modifier (page 1–613) ,
enable Face (or Polygon or Element) sub-object
mode,thenusethefeaturesontheSurface
Properties rollout.
•Converttheobjecttoan
editable mesh (page
1–984)
, enable Face (or Polygon or Element)
sub-object mode, then u se the feature s on the
Surface Properties rollout.
Viewing Smoothing Gr oups
The easiest way to view smoothing is to look at an
object in a shaded viewp ort. In this case, you are
not viewing the smoothing groups themselves but
rather their effects on the shaded surface.
You can see the smoothing group numbers for
selected faces of an editable mesh object or the Edit
Mesh modifier by looking at the Smoothing Group
buttons on the Surface Properties rollout, or of
an editable poly object on the Polygon Properties
rollout.
SmoothingGroupbuttonsappearasfollows:
• Group numbers not used by any face in the
selection, appear normal.
• Groupnumbersusedbyallfacesinthe
selection, appear selected.
• Group numbers used by some, but not al l, faces
in the selection, appear blank.
Automaticall y Smoothing an Object
Click Auto Smooth to assig n smoothing
automatically. You set a Threshold angle to
determine whether to smooth adjacent faces.
• If the angle between face normals is less than or
equal to the threshold, the faces are assig ned to
a common smo othing group.
• If the angle between face normals is greater
than the threshold, the faces are assigned to
separate g roups.
Auto Smooth is found on the Surface Properties
rollout and on the Smooth modifier.
Ma nua lly Appl y ing S moothi ng G roups
You m anually a ssign smoothing groups to a
selection of faces by clicking Smoothing Group
buttonsontheSurfacePropertiesrolloutorthe
Smooth modifier. The smoothing group of each
button you click is ass i gned to the selection.
S electing Faces by S moothing Gr oup
You can also select faces according to the assigned
smoothing g roups. Click Select By SG on the
SurfacePropertiesrollout(editablemesh)or
PolygonPropertiesrollout(editablepoly)andthen
click the smoothing group of the faces to select.
This is a convenient way to examine smoothing
groups on an object someone else created.
Creat ing G e o m etric
Primitives
Geometricprimitives are basic shapes that 3ds Max
provides as
parametric objects (page 3–1083) .
Primitives are divided into two categories:
Standard Primitives (page 1–165)