Silvarret is amazing. I new everything about this apart from the Control+D you make diagonals as 1 building, instead of multiple, and that blew my mind.
Why did Frontier hide some of the advanced tools so much, I will never undertand.
EDIT.
Mmmm, after trying it, it doesnt work very well, as you need to do it at the beggining with one wall only, and after that you dont have the other grids to finsh the other walls if you want them bigger for example.
Prefer the multiple building grids, what we really need is something to copy and move whole building groups easily, as it can get really tedious for super intrincate buildings with multiple grids, if you want to move them to another part, or make a copy of them.