Here is the problem blend: http://bebop.cns.ualberta.ca/~cwant/bad_nan.zip * Tab into edit mode * S to scale * middle mouse to constrain, get it to constrain to X * Hold down control key so it scaling steps by 0.1 * move your mouse onto the 3d cursor so that Size X goes to zero -- blam! Doesn't crash, but reports 'nan' for Size X Chris