thisisnotaspoon you are talking about ‘dish’ and offset of spoke holes.
Generally (as far as I understood it), you want your spokes orientated to oppose the forces at the hub, on a rear disc wheel that means that you build them asymetrically so as to oppose the driving forces on the drive side and the braking forces on the non-drive side.
Top section of this is pretty easy to understand. http://www.peterverdone.com/archive/bikewheels.htm
There is also a good explanation of this in the wheelbuilding section of the Zinn and the art of mountain biking book.