CAD 2 realtime mesh

pailhead

Lately, i've been receiving CAD data that has been previously converted to meshes, with the request for assessment and testing in realtime. I dont' have much experience with Rhino or Catia, but i did notice a couple of things:

1. patches are never connected i.e. there is a split wherever a nurbs patch was,
2. automagically, the normals compensate this, when i import an fbx, even with splits, the normals appear continuous
3. as soon as i do anything, like deleting a face (see attachment), the normals go haywire
4. and at this point, the model appears "buggy" ill have a hard time smoothing this even when welding vertices

Does anyone know what's the idea behind this?

I'm confused by the topology of the model, a part that is completely symmetrical, and looks like it has the same nurbs structure on both sides, comes in with different subdivision (the red borders in the second shot is actually the middle of one such object).

I look at the mesh as 'meat' and normals as something that is projected from the infinitely precise mathematical surface, during the mesh conversion process.

Is there a way to have max, not recompute the normals at some point, but allow for removal of faces, and edge splits?

Eric Chadwick

Max is touchy about dealing with edited normals. I put some tips in here, might help solve your problem.
http://wiki.polycount.com/wiki/VertexNormal#Editing_Normals_in_3ds_Max

The subdivisions are usually controlled in the original CAD app, and can be different for each patch. It sounds like things weren't adjusted properly before they exported.