DMC Clr thresh or Noise thresh

[nomads]

Can some one explain what is the difference between Clr thresh and Noise thresh?

I always used Noise thresh to set my noise quality.


Does enabling Clr thresh mean that the sampling is no longer universal? Different elements are being sampled by Clr thresh and others by Noise threshold? If so what are these things?

I'm confused.

I am still using Vray 2.50.01

[joconnell]

Noise is the threshold in the dmc sampler and it's used to control the level of your material, light and GI sampling. When vray is calculating your lighting and shaders, this is the quality level that it's aiming towards. Colour threshold is in the anti-aliaser and it's what vray uses for your geometric edges and texture sampling to an extent. The idea is that you might have a scene that has really really simple geometry (lets say an empty room) but it might have complex lighting and materials in it (let's say lots of soft lights and a glossy floor). The quality level you need to get clean results on the geometry edges on a simple room are pretty easy to vray, so you might be able to leave your AA colour threshold at something like 0.01. The materials on the other handy might need to be calculated to a finer level to remove all of the noise, so you could use a lower level on your noise threshold there like 0.005. Ultimately everything will end up going back through the AA sampler so if your material or light sampling is really noisey, then AA will try to clean it up a bit more, but if you've got light and material sampling that's being done to a higher standard then the results it'll pass back to the AA sampler then it'll breeze through without AA needing to do any more work.

Having the two samplers linked is just a convenience thing and it works pretty well, but there's a few situations where you might not need your AA to be that high but want your materials really clean so having the option to unlink the two just gives you that option for a bit more speed and flexibility.

[nomads]

Thank you John,

That's a clear explanation.