@Laszlonagy : thanks for your detailed reply. But I knew those tips (I'm not new to ArchiCad at all).
1. Maybe it is also possible in VectorWorks, but that doesn't make it a bad idea, does it ?
2. I know you can do it with the magic wand. But what if I want 400 hatches as slabs ? That means 400 clicks... We often want to model the urban context of our projects...
3. Again, that's a nice feature, but we need that to operate on many objects at once.
4. It's not quite the same : it is effective a reducing dupliates and useless points, but it does not actually simplify a geometry, based on a tolerance. A very common use is with site models : if the imported lines have too many vertexes, you need to simplify those lines.
5. It does not sum up the values. Selecting two slabs gives
1 Slab
Area on Plan, holes considered = 1'115.437 m²
Area on Plan, holes not considered = 1'115.437 m²
1 Slab
Area on Plan, holes considered = 1'098.244 m²
Area on Plan, holes not considered = 1'098.244 m²
An alternative if you really don't want to implement those features : GIVE US A PYTHON API ! I'd be so happy to develop those features as plugins...