Probably the most straightforward would be to model it directly. Start with cubes and get the shapes you want. That would give the most control. You could apply a textured bump map and give it a nice shader and it should be pretty believable.
You can subdivide a polygon mesh and use the sculpt polygon tool to get some of the uneveness, but keep in mind how undisturbed snow actually looks on a roof. It is not very wavy, rather it is quite uniform and flat. It also bulges slightly over edges because the flakes stick to each other.
The script in the video could be a nice addition to the scene but using it to generate such large solid bodies would be impractical. As Stwert suggested, model it. I'd try duplicating some faces on the would be covered objects as a shell that can be extruded. Then sculpting some organic contours either using Maya's sculpt tool or something more robust like Mudbox or Zbrush. And depending on how realistic you want it to be then I'd say the shaders and lighting will play a critical role in whether it looks like actual snow or just weird white clumps of stuff.