Triangle planes in level editor?

[Adny]

thanks 4 help but when I do the 45 degree angle it ends up flickering the texture through the other one
also the roof isnt a perfect 90 degree angle but ill keep trying.

Use welders to create your borders (e.g. wooden beam welder), this allows for a discrepancy in depth. You can move one of the planes slightly more forward or backward than the other to prevent flickering, or misaligned edges (thanks to the welders). You can play with plane tile angle and size to make it flow together very well.