Simple as that a triangle build helper with settings for xyz rotation, the height, angle of the triangle (with options for right triangles, isosceles triangles, and equilateral triangles.
ehhh that's not really needed because it is a block based game after all. and we have the "brush" tool you could make the walls one by one instead of the entire cube.Would be nice to have a box helper to. Where you can create hollow boxes instead of blocks.