Hey all. I've got a bit of a problem that I'm hoping someone can help me with. I'm using Rhino to make a model to print and am having some issues finishing it up. I was doing a boolean difference on the final solid to cut into the bottom of my piece as a final step and noticed that after the boolean runs I've got some weird internal surfaces stretching through the cut out space that shouldn't be there and are not even being cut by the boolean. I'm unable to get rid of them. I've exploded everything and used redraw on the ring that goes around the whole bottom of my model (which the bad surfaces seem to be a part of) which actually does remove them, but as soon as I try to re-join all of the faces it puts the bad surfaces back in, sometimes not even in the same places they were before. Here is what I'm talking about. The bottom of this object used to be capped, but I've removed that surface to address this issue. Please let me know what I can do to fix this. Here is the Rhino 3dm file. https://dl.dropbox.com/u/2561448/Random Mag Cubes.3dm Thanks in advance.