I am trying to add subdivisions to obj. objects, which are buildings from google-earth that have been converted to obj. objects in sketchup pro.
It gives me no subdivision objects and when i go modify>convert>polygons to subdivisions I get this error :
// Error: polyToSubdiv1 (Poly To Subdiv Node): One or more edges is nonmanifold.
// Nonmanifold geometry cannot be converted to a subdivision surface.
// To clean up nonmanifold edges, use Mesh->Cleanup with the nonmanifold option. //
// Error: Command polyToSubdiv failed. Open Script Editor for details. //
This is one of those (rare) error messages that is helpful and tells you exactly what you need to do, which is to use Mesh->Cleanup with the nonmanifold option.
The reason you're getting this messsage is that the mesh contains edges that are shared between three faces (the non-manifolds), something you typically want to avoid, and something that cannot exist in a SubD.