There seems to be a bug in how booleans work in Grasshopper for Rhino 8. Sometimes they only work in a specific case or if grafted. Sometimes they do the wrong thing. I think it might be about the revolution surface. Please see the file attached. Thanks!
231205_booleanBug_pcr.gh (16.5 KB)
I think a part of the issue depends on the fact that the Brep you get by revolution is flipped inwards:
if you deconstruct + Join it, things work the right way:
231205_booleanBug_pcr_Re.gh (21.9 KB)
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Well, yes, you are right. The booleans work with the output from the Revolution though. Technically it should not be flipped as it is a closed Brep. Since I am doing a full revolution it shall be closed. And it is in Rhino, if you bake it. Maybe not a real bug, but just a little weird.
Turns out all extruded surfaces from the standard closed curves (meaning the closed curves themselves) are flipped in the first place. Guess it does not matter until you revolve them 2*pi. Cheers and have a nice day!
well, this also depends on many things like the direction of the revolve axis and the direction of the revolve itself
for instance if you flip the rotation axis (in such a way the line flows along -Z) then you get the the closed solid with the right Normals:
231205_booleanBug_pcr_Re_Re.gh (23.0 KB)
same thing in Rhino, you can visualize it by activating the Backface color in the Display options (in my case backface color is red)
Yes, you are right. Nevertheless I think this is wrong.