Mathematically if you look at the Front Ortho of the image there is the triangle ABC. Length B is the side of the cube L, length A is the length of a faces diagonal L * sqrt(2) (basic pythagorus) The tangent of angle alpha will be L / (L * sqrt(2)) or 1 / sqrt(2) atan of which equates to 35.2644 degrees. The rotation_euler XYZ (45, 35.264, 0) The length of the longest diagonal C is L * sqrt(3), Once again from pythagorus. If the origin is in the middle of the cube translate the cube L * sqrt(3) / 2 to put it on its point. Interestingly the volume can be calculated from The length of the [![enter image description here][1]][1] [1]: https://i.sstatic.net/UHdAK.png