Hi DesuDeus, also you may want to check out that previous message I posted again, where I had several animations in it:

http://moi3d.com/forum/index.php?webtag=MOI&msg=2782.8

Those will probably make more sense now - every time in those animations where you see a dashed line being created, that is one of these special temporary construction lines.

You can see there how you can use it in any drawing command and not just while drawing a line, like there I create a square balanced on a midpoint, and draw an arc balanced around a midpoint, all without leaving those commands.

- Michael