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The presence/absence of normals may affect tessellation. Otherwise, remove unwanted faceting by deleting normals in Katana if they were exported despite your intent to subdivide.

To Duplicate the Geometry Settings from Maya

It may be useful to match what you're seeing in Maya since it may be your primary modeling package. Below are the settings necessary to achieve the same look if you asset was not exported with the data.

1. Create an attribute Script node
   1. In the CEL section, select the mesh(es) where you wish to apply the attributes. In this case we've added the subdmeshes from Maya
      1. Custom CEL statements
         1. /root/world/geo//*{@type == "polymesh"}
         2. /root/world/geo//*{@type == "subdmesh"}
      2. In the script section add the following:
         1. DelAttr( 'geometry.vertex.N')
         2. SetAttr( 'type', ['subdmesh'] )
         3. SetAttr( 'geometry.facevaryinginterpolateboundary', [3] )
         4. SetAttr( 'geometry.facevaryingpropagatecorners', [0] )
         5. SetAttr( 'geometry.interpolateBoundary', [1] )
         6. 'geometry.vertex.N' (Note: This deletes the existing normals off the mesh as renderman will create its own for a SubD mesh. This is explained in the above section.)
         7. 'type' changes the mesh to a subdivisional surface
2. We set several attributes above to match the Maya settings. Below we list the other options should you need to experiment.
   
   1. Options for geometry.facevaryinterpolateboundary
      1. 0(old style)
      2. 1(new style)
      3. 2(new style, no corners)
      4. 3(new style, smooth internal only) This is the current Maya default
   2. Options for 'geometry.facevaryingpropogatecorners'
      1. 0(off) This is Maya default
      2. 1(on)
   3. Options for 'geometry.interpolateBoundary'
      1. 0(no interpolation)
      2. 1(edge crease, corner crease) This is the Maya default
      3. 2(edge crease only)

For Developers

If you are implementing support in a custom Katana plugin for subdivision surfaces, you will be interested in how RenderMan for Katana translates geometry attributes to RenderMan's subdivision format.  See the developer documentation here.

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