edit: The above comment https://news.ycombinator.com/item?id=6123729 https://news.ycombinator.com/item?id=6123729 is more correct than I am I think :) Extracti

edit: The above comment https://news.ycombinator.com/item?id=6123729 https://news.ycombinator.com/item?id=6123729 is more correct than I am I think :) Extracting the spatial information is a subset of the same problem, I think. Things like tomographic reconstruction use either multiple rays through the same object or parallel rays through the object at different angles, but this gives density through the object and from that the volume and its shape. If you consider the same problem where you have no density or 100% density, you get the spatial information from multiple 2d objects. I ran into this when playing with IDL ages ago: http://northstar-www.dartmouth.edu/doc/idl/html_6.2/VOXEL_PROJ.html http://northstar-www.dartmouth.edu/doc/idl/html_6.2/VOXEL_PR... and learned about the rest from the references there. I'm not really savvy on the problems though so the math could be totally different and unrelated, but I think you can accomplish the same thing with either method.