Digital Surface Model (point cloud) to Mesh

Hi all,

I have a point cloud that represents the elevation map of a small neighborhood (on the right):

I would like to create a mesh from these points in order to reconstruct the buildings (i.e. to make them look like the geometries on the left, but with more realistic rooftops). However, there are no points with same X, Y and different Z in this point cloud, so the problem becomes more complex...

So far, I have tried the plug-in "Resurf for Rhino" and commands such as "RsPointCloud2mesh", but the result is not good and it creates holes where building facades should be.

Another option would be to script a way to reconstruct vertical surfaces taking the heights as the diference between the highest and lowest point... But something tells me that my question should have a relatively straightforward answer...

Thanks in advance!

Sara