boolean woes/bug?

Blender 2.41…
I am attempting to do a simple difference between two objects. Both, as far as I can tell are closed meshes. I have a cylinder I have extruded, scaled and etc. and and trying do a boolean difference with just a plain cylinder. Problem is, I keep getting an error saying both meshes must be closed (or words to that effect…). The boolean ops seem to work ok for primatives, but not for this. Is it me, or a bug? I’m loosing chin whiskers over this…Any help
would be greatly appreciated!

thanx in advance!

.blend file here:

The more complex cylinder is not closed. Some vertices at the bottom are not connected to the side. Do this, in the edit mode, deselect all vertices, press the spacebar and go to Select/Non-Manifold. You will notice that those vertices are highlighted. You could connect them by slightly raising the tolerance for the Remove doubles. The default is .001 Try raising it to .003 and press the RemDoub button. This should close the mesh. But doing a boolean on this seems to freeze Blender. Perhaps try to simplify the objects involved first by separating the larger part of the cylinder, closing it then applying the boolean. You could reconnect them again later…

Yes, the non manifold selection let me know about the mesh. Also, the increase proximity in remove doubles did indeed close the mesh.(funny though, started with a cylinder and only extruded,scaled,etc.) Thank you, I needed to know this. Also, yes, it crashes blender when trying to do the operation…
I let the ram go from appx. 123 meg to 55 meg before I quit. looks like maybe a bug? ([email protected]+ghz hyperthreading and fans blowing full tilt!)
It looks like for now such operations should be done on primatives first, then expanded on.

again, thanx…cool… :slight_smile: