Artaud,

On a side note, Regarding construction lines, There is a script that allows you to "keep" them around for longer than the current operation. If you havnt seen this, you should check it out. "Petr's Moi Page" from the "Resources" tab on The MoI home page:

http://kyticka.webzdarma.cz/3d/moi/

Its an inline script. Look at "CLine" link.

Nice work!
Burr