well in this its pretty easy alls you need to do:

1st:make your background a plain color(black, blue, green, white etc.)

2nd: make the polygon how you want it to be

3rd: get the scenery mm1 or blank and make it the color of your background and make sure its set for Front then place it over the polygon

I hope this helps you with your maps :D

I think everyone knows how to do invisible polys without tutorial.

If you really want to have invisible polys use polyworks, make the poly untextured, and color the poly the same color as the background.

umm...In polyworks there's an option to make invisible polys...

Pride gets 10 points for being the only one who answered this topic logically.