Diff problem

 From:  Michael Gibson
268.3 In reply to 268.2 
Yes for the time being the booleans tend to get a little confused with open (non-solid) objects.

Until I get a chance to tune this up you should either solidify the object like Petr mentioned, or an alternative to that is to use the Edit/Trim command to cut the objects with each other and leave the pieces behind, then do an Edit/Join to join the pieces together.

- Michael