Which GI methods the Renderer like Vray,Brazil use?

[playmesumch00ns]

mental ray offers both photon mapping and qmc hemisphere sampling with irradiance caching.

from what I can see, vray's lightmap is something similar to bidirectional path tracing with irradiance caching.

What's interesting is mental images have successfully patented qmc sampling:

http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=CA2449684

The patent's not much fun to read, but it looks like they've patented the use of certain low-discrepancy sequences and algorithms for manipulating them for the purpose of light transport estimation. God knows how enforcable any of this is, I guess we'll see when it comes to court.

[soulburn3d]

Brazil currently has photon mapping and Quasi Monte Carlo as well.

- Neil

[JayHoo]

You really helped me. In the online Vray help i have found the GI methods for Vray. :)

[thev]

mental ray offers both photon mapping and qmc hemisphere sampling with irradiance caching.

from what I can see, vray's lightmap is something similar to bidirectional path tracing with irradiance caching.

What's interesting is mental images have successfully patented qmc sampling:

http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=CA2449684

The patent's not much fun to read, but it looks like they've patented the use of certain low-discrepancy sequences and algorithms for manipulating them for the purpose of light transport estimation. God knows how enforcable any of this is, I guess we'll see when it comes to court.The patent (as well as others from mental images) is not about QMC sampling in general; it describes only a very specific implementation of qmc raytracing.

[cpnichols]

from what I can see, vray's lightmap is something similar to bidirectional path tracing with irradiance caching.



Well sorta... They have actually changed the name to Light Cache now. It is sorta like a inverse photon mapping. Taking the best part of photon-mapping (bouncing the light around a lot), and the best part of Irradiance chache (which is similar to Final Gather), by optimizing it to the view. Basically think of it like a inverse photon map. Where it sub-divides the viewport to samples that fires them off bouncing around... A LOT. The big advantage of ligh cache (besides it speed) is that it is effective infinit light bounces, or basically it will stop bouncing when it it is no longer effective.

Basically Vray has 4 methods:
Irradiance Cache is like final gather in MR (but faster IMHO)
Photomapping is like everyone else
QMC, is similar to Brazil, Arnold, etc....
Light Cache... I just explained
their is also PPT (progressive path tracing) which is based off Ligh Cache. This is somewhat similar to the way that Maxwell works.

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