Question about the co-edge notion

Genreally in solid modellers there is the notion of co-edge. But i just couldn't find it in the documentation of Cascade. Could any one show me where to find in the doc if it exists, and if not, could the matradatavision engineers explain why this notion isn't used in Cascade, and if there is an equivalent in the cascade classes ? Best Regards Omar Msaaf

Débarbouillé Gilles's picture

Yes this notion already exist in Open CASCADE and is also generalized for all the shapes.

If you have a look at the TopoDS package you can see the two root classes which are Shape and TShape.

The TShape is what you call co-xxx. It is the definition of the shape and is manipulated by Handle. It is a shared object referenced by an upper topological object.

The Shape is how the TShape is used, where it is located, with an orientation in regard of the upper Shape. This object is manipulated by value.

So for the edges you have a unique description which is supported by the TEdge and for the two adjacent faces you reference this TEdge respectively by two Edge objects with opposite orientation.

If now you have a look to a prism, the lower base and the upper base share the same TFace by respectively two Face objects with different Location and opposite orientation.

Best Regards