I have a very dense point cloud (billions of points) of the exterior of a building obtained by laser scanning it with a Leica head. I successfully subsampled it down to around 500,000 and I'm trying to print the building by first creating a mesh. I tried using CloudCompare, Meshlab and PDAL, using Poisson surface reconstruction. However, the resulting mesh is full of holes, mainly in the roofs which have the lowest point density, and I cannot print it. Is there any algorithm which could use the fact that the point cloud is precisely the exterior part of a geometric thing?