Pixar OpenSubdiv

A 502 polygons sun glasses model (left) subdivided and smoothed in render time using Pixar's Catmull-Clark subdivision mode (right) 


The Subdivision modifier implements Pixar OpenSubDiv subdivision modes to subdivide low-polygonal objects into smooth surfaces. The main advantage of using this modifier is that as the subdivision is performed only at render time, you can keep your MXS scenes light, and thus they will open faster, take up less space on your harddrive and also transfer faster over your network when doing network rendering


A quick look to the Pixar OpenSubdiv modifier and its parameters



The Subdivision modifier panel in Studio



Indicates the number of iterative subdivisions of the object. 


Allows you to choose between Loop and Catmull-Clark subdivision algorithms. 

UV Interpolation 

Allows you to choose the interpolation of the UV coordinates for the new geometry, choosing from (taken from Pixar's specification): 

  • None: No boundary interpolation behavior occurs 
  • Edges: All the boundary edge-chains are sharp creases; boundary vertices are not affected 
  • Edges and Corners: All the boundary edge-chains are sharp creases and boundary vertices with exactly two incident edges are sharp corners 
  • Sharp: Smooths only near vertices that are not at a discontinuous boundary. All vertices on a discontinuous boundary are subdivided with a sharp rule (interpolated through). 

Edge Crease 

When set to 0, the polygon is divided evenly at the middle of its length. A higher value approximates the new edge to the original edge, concentrating the subdivision near the edge. This setting is useful to bevel the edges of the model. 

Smooth Angle 

Angle between two polygons below which the normals are not smoothed after the subdivision, maintaining their original orientation. 


To learn more

See more information about the Pixar OpenSubdiv specification in the Open SubDiv Documentation site.

OpenSubdiv is owned by Pixar. Copyright by Pixar. All rights reserved.