Select the DTM 3d element and you'll have a reference plane that follows the terrain. So when you add walls and other elements that use reference planes they will automatically follow the shape of the land. There is nothing easier for adding Beams, rafters, and various rafter tails. If you alter the pitch of the roof, the rafters automatically follow. There's a command to create beams along a roof's hip or valley.
Nothing comes close to it's speed and versatility.
An expanded version of the v12.3 roof command, with more umpf. After creating your roofing plane, these tools will allow you to refine and edit the roof. With this module you should be able to create any type of roof quickly and easily with skylights, dormers and what ever else you want to add. I use to dread roofing layout, but not any more. On the contrary, I have fun trying to create new ones.