OTOY Forums

Is there anyone who can help me to understand the settings of PMC Kernel?
I tried doing a render with this kernel, but I do not know how to set the best settings.
I'd like to read the manual but for now does not exist the latest version.

Can you help me please

nobody knows how to use the pmc kernel and know what are all settings that I see inside?
Without the manual I can not understand their functionality..

thank you very much

I can tell you its best to use the default settings. However i suggest using the search button that is how i know the following info about PMC.No guarantee that the info is correct...
maxdepth -> maximum bounces of a ray from a given surface.
rrprob-> russian roulette probability is a way to reduce the average depth of a ray (number of bounces) in an unbiased way. It could increase the msamples/second 3x-4x times but there will be some dark areas and as much i can tell some refractions turn black from white.
rayepsilon-> not 100% sure but it is about the distance between 2 faces. If you have a lable on a bottle and it renders black (because it is too close to the bottle surface) or you have a glass on a table and same issue it is because rayepsilon is too big. Zero should solve the problem.
exploration strength-> i think it is about the contribution of the total bounces . Always the contribution of the first few ray bounces is the biggest and most important. So if you put it high this could give blown out images because the contribution of lets say the 10th bounce still matters.
direct light importance-> probably you have noticed that the most of the noise is on the surfaces that are hit indirectly by light this tells octane how much filtering to focus on surfaces hit by direct light.
maxrejects -> i think lower value will produce smoother image but may introduce bias.Higher value samples will be spaced more equally(high level noise) harder for caustics.
I think its the same parameter for luxrender. It has to do with the render getting stuck into very bright samples and miss calculating their light contribution.
All other parameters should be self explanatory. You better disregard this info and wait for an official...

• rayepsilon is the minimum distance between two planes. It should be set according to the scale of the scene. If it is to big, artefacts like telemmaite described will appear in the scene, but if it is too small, due to numerical instabilities in ray tracing, rays traced from a surface point may intersect at the surface itself, resulting in noise patterns on surfaces. (This problem is sometimes called surface acne.)
• rrprob gives the chance a ray is continued at any bounce (and thus influences the average ray depth and the speed). Lower values give more samples per second, but more noise in indirect light. If set to 0, the probability is derived from the proportion of light reflected at each bounce, which is adequate for most scenes.
• exploration strength gives the tendency of the PMC kernel to investigate paths with a significant brightness longer.
• direct light importance decreases the amount of computation done on direct lighting, rather than indirect light.
• maxrejects: a lower value decreases noise, but introduces bias in scenes with high contrast.

--
Roeland

Edit - corrected mistake in rrprob explenation.

Thanks all..i will try to play whit this setting..

Thanks a lot