Fast Lossy Compression of 3D Unit Vector Sets

Sylvain Rousseau and Tamy Boubekeur
ACM SIGGRAPH Asia 2017 Technical Brief

Fast Lossy Compression of 3D Unit Vector Sets
1: Unit vectors are grouped according to their spherical coordinates. 2: For each group (window), we apply a uniform mapping that relocates subparts to the whole surface of the unit sphere. 3: To compress the vectors, we apply any existing unit vector quantization with an improved precision.


We propose a new efficient ray compression method to be used prior to transmission in a distributed Monte Carlo rendering engine. In particular, we introduce a new compression scheme for unorganized unit vector sets (ray directions) which, combined with state-of-the-art positional compression (ray origin), provides a significant gain in precision compared to classical ray quantization techniques. Given a ray set which directions lie in a subset of the Gauss sphere, our key idea consists in mapping it to the surface of the whole unit sphere, for which collaborative compression achieves a high signal-over-noise ratio. As a result, the rendering engine can distribute efficiently massive ray waves over large heterogeneous networks, with potentially low bandwidth. This opens a way toward Monte Carlo rendering in cloud computing, without the need to access specialized hardware such as rendering farms, to harvest the latent horsepower present in public institutions or companies.



 author = {Rousseau, Sylvain and Boubekeur, Tamy},
 title = {Fast Lossy Compression of 3D Unit Vector Sets},
 booktitle = {SIGGRAPH Asia 2017 Technical Briefs},
 series = {SA '17},
 year = {2017},
 isbn = {978-1-4503-5406-6},
 location = {Bangkok, Thailand},
 pages = {23:1--23:4},
 articleno = {23},
 numpages = {4},
 url = {},
 doi = {10.1145/3145749.3149436},
 acmid = {3149436},
 publisher = {ACM},
 address = {New York, NY, USA},
 keywords = {direction field compression, ray wave compression, unorganized normal vector set compression},