UV Mapping on huge meshes


I just created some meshes out of my large point clouds (Large means Vertices >600k). For visualization purposes I want to fit a texture on it.
The problem here is that the model has different dimensions than the image, so I need to scale and move it to the right positions.

I read some tutorials on UV mapping in blender, but they weren’t that usefull because Blender crashes when unwrapping the mesh (I guess the mesh was too big). Another approach was the option “project from view”, when I used the top view. The problem here was that I could load the vertices, but it needs so much memory that I couldn’t work with it.

So I want to ask. Doas anyone have a simple solution or knows another way of doing this? In best case it would be something like this http://info.photomodeler.com/blog/bid/222327/Tip-20-Color-and-Texture-an-Imported-Point-Cloud-in-PhotoModeler in a freeware version. I also don’t mind non blender solutions or working/coloring just the vertices.

Thanks in advance for any idea.

A quick solution in Blender would be to add a Decimate modifier and decimate your very high poly mesh so it is more workable with the unwrapping then apply the modifier. Just be sure to backup your original high poly mesh (or just duplicate it and put that duplicate in another layer so you don’t lose it)

A less quick solution would be to make a retopo to end with a lower poly version of the high poly mesh.

With a lower poly mesh, the unwrap will have no problem to do its work in Blender

if the camera in blender corresponds to the camera in the texture point of view, you can always use the ‘Camera’ from the texture coordinates node.
if you are planning an animation, you can use this ‘camera’ input as a texture and bake it, and use it as a uv in the animated render.