[needhelp596]

Hi everyone. I'm new to Rhino (coming from SolidWorks) and am struggling to build a part. I started with a mesh that i turned into a closed polysurface and want to create a sphere encompassing this polysurface and create a shell whose outer surface is the sphere surface and the inner surface is the polysurface.

When use boolean difference I get "Objects do not intersect", which i don't understand. The outer surface of the sphere does not intersect the surface, but the sphere should be filled and the polysurface definitely takes up volume inside the sphere.

If I create a rectangular prism and use boolean difference with that and the polysurface I get "Boolean Difference failed".

Can someone tell me why this isn't working?

-Thanks

[awerby]

Unlike Solidworks, which is a solids modeler, Rhino is a surface modeler. Unless the surfaces of your spheres intersect, it won't do a Boolean operation; to Rhino these read as two separate closed surfaces nested inside one another. If you create a tunnel between them, you can split it at each surface, and split the surfaces of the spheres, to get a shell (with a hole in it). But the space between the outer and inner surfaces will still be empty as far as Rhino's concerned.

[victorofga]

following a kind of logic, you might create 2 half sphere, sutract of each, then unify the two half..

still hard to imgine the reason to making hollow a sphere this way...

[BrendaEM]

Generally, without conversion, I do not think that you can subtract a mesh from a NURBS object.

Rhino is a solid modeler, just as SolidWorks is, though because it's NURBS based, the resulting object must be a manifold object. So, object such as hourglass or a tennis ball must have a seam somewhere.