Exterior boundary of shape.

[Balder]

I quote : "A solid is expected to contain a single shell that describes its external boundary. If there are two or more shells, it's considered to be a solid with voids".
The solids I import from step files does not seem to have this property. A complex solid with several holes only have one shell.
I also tried the method descibed her : https://dev.opencascade.org/content/how-get-external-and-internal-boundary-holes-edges-mesh-face, but her i get 0 wires.
What am i missing and whar can I do to extract the external boundary of a shape ?

Tommy

 

[Andrey]

What in your understanding is the external boundary of a shape? Could you fully describe the problem? Could you attach the shape if it's not difficult? Or at least a picture?

 

[Balder]

To get the outer/external shape from a polygon i just search for polygons stored clockwise fashion. Interior polygon (hole parts) , which are stored counter-clockwise. I juster wounder i there is a way to do the same thing for solids.

Like this one, i would like the shape, but without the holes. This one is one solid.

 

[Quaoar]

The solids I import from step files does not seem to have this property. A complex solid with several holes only have one shell.

When they say "with voids" they mean an entirely enclosed cavity, like, for example, an inner box subtracted from another box. Such cavities are not visible from the exterior of a part, and they are not manufacturable with traditional subtractive methods (although they can be 3D printed). If you want to get rid of hole and alike features, then normally you first automatically detect those features based on some topological and geometric heuristics (like here: http://analysissitus.org/features/features_recognize-cavities.html) and then eliminate them from the model by cutting them off from the B-rep structure and (generally) stitching the neighboring faces together. Is that what you're looking for? If you attach a STEP file, it would be easier to help.