This is a neat approach. Basically it is a combination of:

(1) Fitting 3D stock models to existing models using a simple but interactive ray casting approach.

(2) Estimating soft lighting on objects fairly convincingly.

(3) Re-rendering the stock models using the artificial lighting and textures of the original photographs.

It is a pretty cool approach. There are real limitations to this but I think that the automated lighting estimate is just cool and has wide applications in the visual effects space.