"polyface mesh" to "3d solid"

[tricota]

HI, I'm on 3DMAX7 and ACAD2007. I have some .MAX buildings that I want to do some sections in ACAD using the "section plane" tool. The problem is that 3DMax export "polyface mesh", and the "section plane" tool only works for "3d solids".

 

 

Is there any way to convert "polyface mesh" objects into "3d solid" ?

The "convert to solid" option says "object cannot be converted".

 

THANKS IN ADVANCE!!!!

 

TRICO