Start with as few faces as possible

A dense subdivision base mesh wastes control points and will reduce performance.

If you want to convert an existing mesh, try using Mesh > Reduce to reduce the number of faces in the mesh.

Use mostly 4-sided polygons (quads)

While subdivision surfaces can handle up to 256 sided polygons, you will get best results from using mostly 4-sided polygons.

When modeling subdivision surfaces, try to avoid faces with more or less than 4 sides, and vertices with more or less than 4 adjacent faces.

When a face or patch on the original surface is not 4-sided, an extraordinary vertex (a vertex with less than or more than 4 adjacent faces) is created at level 0 of the subdivision surface. This affects the parameterization of the subdivision surface and might make the surface bumpy (the bigger the quads relative to the model, the less this is a problem).

Put vertices and edges in the polygon mesh where you want them in the subdivision surface

If you can plan out where you want vertices and edges in the model, it will help you produce the results you want when modeling and binding the surface to joints.

For example, edges must be present where you want to create a partial or full crease, and as with polygonal and NURBS surfaces, edges should circle the eyes and mouth on the model of a head.

Watch out for polygons that will not convert

You cannot create subdivision surfaces from the following types of polygonal surfaces.

• Nonuniform topology.

  

  Use Mesh > Cleanup to correct nonmanifold geometry.

• Lamina topology (faces are on top of each other sharing more than two vertices or more than one edge).

  Use Mesh > Cleanup to correct lamina geometry.

• Free points or floating edges.
• Interior vertices with two incident edges.
• Inconsistent normals.

  One way to correct inconsistent normals is to use Normals > Conform.