On recreating Harry Potter:
The first step is masking out objects in the scene so that we can turn those objects 3-D,” says IMAX’s Eric Robinson as he shows off the software. “The next step is, re-create the scene in 3-D so that we can generate depth information from that. Our proprietary render system generates a new image, which is offset from the original.
P.S. The rest of the clip is all marketing cr*p, skip after 01:00. See the clip here