TopExp_Explorer shape enumeration

I am having difficulties retrieving a map of all the subshapes of my compound. It consists of a lot of faces, edges and vertices. If I do a

for( TopExp_Explorer it( shape, TopAbs_ShapeEnum::TopAbs_FACE ); it.More(); it.Next() )
{
Console::WriteLine( "FACE" );
}

I get lots of Faces, but if I try the more general approach,

for( TopExp_Explorer it( shape, TopAbs_ShapeEnum::TopAbs_SHAPE ); it.More(); it.Next() )
{
Console::WriteLine( "SHAPE" );
}

I dont get anything.

Any ideas?
Thanks, Kuni

kunigunde's picture

Am I missing the role of TopAbs_SHAPE?
From the example under "5.4.1 Use of TopTools_Map" in the OCC "Modeling Data User's Guide" I would assume, that every kind of topology entity, like vertex, face, compound, etc. IS a TopAbs_SHAPE, so I can retrieve them all by querying simply for shapes. But this doesn't seem to be the case, TopAbs_SHAPE seems to be a seperate topology type. But why then is every other topology type inherited from TopAbs_SHAPE?

I am confused.
Regards, Kuni

kunigunde's picture

From TopExp_Explorer.hxx:

//! * The type of Shapes to find : e.g VERTEX, EDGE.
//! This type cannot be SHAPE.

Grrrrrrr, why then is it in the examples?

Kuni

wei guo's picture

Hi, Kuni,

I am afraid that TopAbs_SHAPE doesn't mean a general shape. For example, if we check file topexp_explorer.hxx, we can find that ToAvoid has default value as TopAbs_SHAPE, while it doen't mean that you will avoid any shape. So we can have the conclusion that TopAbs_SHAPE is not a general shape but just for None shape.

I have the same question that there are much more faces than what I want. In fact, I just need those faces for triangulation and I find that lots of faces with Orientation 0. So I may plan to omit those one and only target faces with orientation as 1. I am not sure whether I may miss some faces and it is my 2 cents.

Best regard,

Wei