Abstract : Modern compositing software permit to linearly recombine different 3D rendered outputs (e.g., diffuse and reflection shading) in
post-process, providing for simple but interactive appearance manipulations. Renderers also routinely provide auxiliary buffers
(e.g., normals, positions) that may be used to add local light sources or depth-of-field effects at the compositing stage. These
methods are attractive both in product design and movie production, as they allow designers and technical directors to test
different ideas without having to re-render an entire 3D scene.
We extend this approach to the editing of local shape: users modify the rendered normal buffer, and our system automatically
modifies diffuse and reflection buffers to provide a plausible result. Our method is based on the reconstruction of a pair of diffuse
and reflection prefiltered environment maps for each distinct object/material appearing in the image. We seamlessly combine
the reconstructed buffers in a recompositing pipeline that works in real-time on the GPU using arbitrarily modified normals.