Triangle planes in level editor?

[TheGreatCthulhu]

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.

Yeah. And if the wall needs to be visible from both sides, you can "sandwich" the rotated plane, so that the lower part isn't visible, and maybe use a welder (like a beam) to hide the top edge, where the "triangle" emerges.

Er... modelling isn't the question. I don't think he wants to handle modelling programs, so just 45 degrees on the plane should work.

Well, he wants to make a house, and that's, broadly speaking, modeling - making it with planes can work, but depending on how it's going to be used in the game, it might not be the best option (if it's something that can only be seen from afar, than it can work nicely; if the OP needs the player to be able to go inside and look around, then, generally speaking, it's not going to look very realistic - but with some effort I suppose it can turn out to be at least decent looking).