Smooth Modifier

Smoothing eliminates the facets on geometry by grouping faces into smoothing groups. At render time, faces in the same smoothing group appear as a smooth surface.

Select an object. > Modify panel > Modifier List > Object-Space Modifiers > Smooth
Standard menu: Select an object. > Modifiers menu > Mesh Editing > Smooth
Enhanced menu: Select an object. > Modifiers menu > Geometry (Convert to Mesh) > Smooth

The Smooth modifier provides auto-smoothing based on the angle of adjacent faces. You can apply new smoothing groups to objects.

1. No smoothing applied

2. Smoothing threshold=15

3. Smoothing threshold=30

Patches

As of 3ds Max 4, patch objects coming up the modifier stack are not converted to a mesh by this modifier. A patch object input to the Material modifier retains its patch definition. Files that contain patch objects with the Material modifier from previous versions of 3ds Max will be converted to meshes to maintain backward compatibility.

Procedures

To smooth an object:

Select the object to smooth.
On the Modifiers menu, choose Mesh Editing Smooth.
On the Modify panel Modifier List, choose Object-Space Modifiers Smooth.
Turn on Auto Smooth and adjust the Threshold for the desired smoothing effect.

To apply smoothing groups manually:

Select an object.
Use a Mesh Select modifier to select the faces to be smoothed.
Click a numbered button to apply the corresponding smoothing group to the selected faces.

Interface

Parameters rollout

Auto Smooth: If Auto Smooth is selected, the object is auto-smoothed using the (animatable) threshold specified by the Threshold setting below it. Auto Smooth sets the smoothing groups based on the angle between faces. Any two adjacent faces are put in the same smoothing group if the angle between their normals is less than the threshold angle.
Prevent Indirect Smoothing: Turn on to prevent smoothing 'leaks" when using Auto Smooth. If you apply Auto Smooth to an object, and portions of that object that should not be smoothed become smoothed, then turn on Prevent Indirect Smoothing to see if it corrects the problem.
Threshold: Specifies the threshold angle in degrees. Any two adjacent faces are put in the same smoothing group if the angle between their normals is less than the threshold angle.

Smoothing Groups group

The grid of 32 buttons shows which smoothing groups are used by the selected faces, and are used to assign smoothing groups manually to selected faces.