Hi:I have a bad 2d autocad file where a lot of lines are not flat, what I mean is that some of the lines have non-zero Z coordinate, I was wondering if there is a way to modify the lines z coordinates without going trough each one, because they are above 5,000 lines.I have tried doing so through the properties box but because these lines are different types, polylines, lines etc.Thanks in advanced

try using the flatten command. or using the properties command first select all the lines and change the start z and end z valies to 0. then select all the Plines and change the elevation to 0