Object inside a glass sphere

[VeronikaB]

I would like to create a glass sphere with a letter in it. But if I simply place a 3D letter into a glass sphere, it is rendered with distortion caused by the solid glass sphere. How to get rid of this distortion? I haven't managed to create a hollow sphere in Rhino. From what I read on Boolean operations, the solution might be to have two spheres without doing the difference and fix the problem while rendering. But I haven't got a clue how...

Any ideas? Thanks.

[Micha_cg]

All glass surfaces of one "real world object" must be joined to one object, but you can't joint not connected NURBS surfaces. If you convert the NURBS to meshes and flip the normal dir of the letters to inside and join all than you should get a physical correct look. The normal direction of glass surfaces must show to the air side always.

I hope my explanation can be understand.

[VeronikaB]

Thanks for your reply, Micha_cg. I converted the letters to mesh and flipped the direction, but it didn't help: BooleanUnion still wouldn't work and the render was the same as before.

I can remove the distortion by setting the glass's IOR to 1, but that defeats the purpose of having shiny glass in the first place...

[Micha_cg]

BooleanUnion works only for NURBS object that are in touch. That's the reason why you should use the mesh trick and don't forget to join the letters with the sphere mesh. Only so Vray know that all this parts are parts of a single object and the ray calculation can be physical correct.

[VeronikaB]

Still no luck, I'm afraid. I created two spheres, converted the inner one to a mesh (also tried to convert both), converted the letter to mesh and flipped the letter. I still can't join the letter to the inner sphere unless the letter touches the sphere. But it doesn't make a difference anyway, the render is still not "correct" in either case (i.e., lots of distortion and even colour change if the NURBS have been converted to meshes).

[Micha_cg]

Only I know the way how it should be done (meshing all (!) parts of the glass object, set the right normal dir and join) and the result should be like at the real world. Attached a quick test.