hi guys,
i really need your help. i’ve been just hired and they are already asking me something i dont have any idea how to do. my problem is basically i have to subtract and make a difference between a closed solid prismatic (cube) with an open poligonal mesh , like a surface. i’ve tried to convert the mesh into nurbs to use boolerian difference but i doest work. please help me i have to finish this work until next week and perform the setting in front of my boss.
hope someone can help me not to be fired 
Can you share your file?
Meshes and NURBS are different animals - you cannot combine them. It’s relatively difficult to get something workable using MeshToNurb - it works OK under certain specific conditions but its purpose is not reverse engineering - so your main alternative here is to convert your “closed solid prismatic (cube)” into a mesh and then try using the Mesh Boolean operations (MeshBooleanDifference, etc.). The result - if it works, mesh Booleans are somewhat unreliable in Rhino - will be a mesh.
There is no reason for you to get fired over this, but you might have to explain to your boss that not all 3D representation systems are compatible/interchangeable.
–Mitch
thanks a lot guys. the problem is that i cannot upload the file due patent issues. the second problem then is that this work has been done already by a competitor, so he want us able to do it too. i was surfing the net and i found some plug ins that allows to convert mesh (20000 faces in my case) to a SIngle surface: could be this an option to do boolerian difference between the solid and the single nurbs surface?
thanks
for the file you can image a mesh half sfere inside a cube, and u have to wipe out the sfere volume inside the cube…
Depending on the shape of the mesh, if it is simple and does not close in on itself too much,you might get something use-able if you run Patch on it.
-Pascal
Hi, if you expect others to spend their time for free to help you not loose your job then the least you can do is to spend some time to make a similar setup to the one you work on.
Trying to explain 3D in plain text is a waste of time.
Tnks for your time guys. Ive done te job using booleanmesh, convertimg all the objects to mesh.
I really appreciate your help!