Revolve surface question


I’m making a hourglass. I’ve made it using the revolve command. But I want the object to be a solid difference between the big one and the small one, I want a hollow solid. BooleanDifference wont do it because solids aren’t in contact. Is there a revolve surface command or something similar?

I think that is all Rhino makes is a”Hollow Solid”. I don’t understand the question. Have you revolved the two curves to make the hour glass? Can you be more specific on what your wanting or what the end result will be used for?—-Mark
Are you wanting a casting mold?

Hi @user1071
If you are looking for a hollow solid, this is not something that Rhino will create using the boolean operations, as Rhino is a surface modeler, not a solid modeler. A volume completely encompassing another will just be two volumes. You can force Rhino into creating a hollow solid, though.
Start by revolveing your curves, so that you have two solids, one larger than the other. Now run NonManifoldMerge on the two - the result a solid that consists of both surfaces, but is still solid. Now run CreateRegions on this geometry, and you will have a copy of the outer surface, a copy of the inner surface and a hollow polysurface - which I guess is what you are looking for. Beware that this kind of volume will potentially give you some really weird problems down the road, so unless you have a specific need, best to avoid it.
HTH, Jakob
Edit: Use Clippingplane to check the resulting geometry

you should add what you are using is for.

Hi Jacob! This was what I was looking for. Thank you! It is only for render purposes, as I think that it’s better to simulate the glass as a solid instead of two surfaces, isn’t it?