Hi Kevin,

> Is the "Manifold Solid B-Rep Object Entity (Type 186)" in IGES not used?

Historically it is just not as common as individual surfaces.


> or is it a weaker implementation as in STEP?

I don't really know off the top of my head exactly how IGES entity 186 compares to object structures in STEP. But I kind of think they are generally similar in idea though.


> or does it not even describe the true solid?

IGES entity 186 I believe does describe a true solid.

- Michael