Boolean difference of a Box in Box

[Willem (Willem Derks)]

Hi Karl,

Have a look at this topic, it is are about the same issue you have:

Creating a hollow solid object

You can do this in Rhino with polysurfaces. It is generally not recommended, since the result may not behave as expected in other Rhino operations, but should be fine for your purposes. Make the inner and outer polysurfaces. Call NonmanifoldMerge selecting both, Call CreateRegions on the result. Delete the inner region. Chuck Welsh Robert McNeel and Associates

HTH
-Willem