Merge pull request #1948 from eoineoineoin/PhysicsSubdivisionDocs

Clarify mesh subdivision options in physics documentation

(Internal change: 2247813)

pxr/usd/usdPhysics/overview.dox

@@ -379,6 +379,12 @@ a bounding sphere. If an implementation does not support a particular kind of
 approximation, it is recommended that it falls back to the most similar 
 supported option.
 
+Note that use of the subdivision attribute (\ref
+UsdGeomMesh::GetSubdivisionSchemeAttr()) can cause features such as corners and
+edges to be removed from the graphical representation. In order to ensure the
+physics representation accurately matches the graphical representation, this
+attribute should be accounted for when generating physics colliders.
+
 Collision meshes may be specified explicitly (for example one that was 
 processed by a particular decimator) by adding the custom collider mesh as a 
 sibling to the original graphics mesh, UsdGeomImageable _purpose_ to "guide" so