Ryan: (The real problem for the CAD software is to determine the vector normal for the edges of the 3d solid. Since you have two edges that share a common edge the vectors point in opposite directions for the same edge. You can't have two vecotrs define the surface normal in a surface definition. That is what causes the problem.)
I have ... two edges that share a common edge the vectors point in opposite directions for the same edge
and I am still able to do solid.
So why it is alowed?
In your sample vectors of two surfaces in the contact location are same and are opposite, just like mine.
So its is the programing.
I have to go back to my work, I am not on the payroll or benefit plan.
@milanw- Sorry I can't open the part. Must be ST8.
Anyway, I hoping the following text from the Parasolid XT Reference document helps clarify things.
"Restrictions on entity relationships for manifold body types Solid, sheet, and wire bodies are best regarded as special cases of the topological model; for convenience we call them the manifold body types (although as stated above, a general body may also be manifold). In particular, bodies of these manifold types must obey the following constraints:
I am not sure all the techy math explanations help. Let me summarize here:
1. Most modern CAD systems use Parasolid -- the best solid modeling kernel around. Used by Solid Edge, NX, and SolidWorks to name a few.
2. The "non-manifold" condition is not allowed in Parasolid when solid modeling. Therefore it is not allowed in Solid Edge (or NX or SolidWorks or...)
3. Parasolid is written and maintained by the brightest set of PHD mathematicians on the planet. So whatever the math reason, it is unlikely to change.
4. So we all accept it and move on.