DMC sampler vs Image sampler

[BillyRaygun]

Dear Forum,

When using IC/LC, is it best to adjust on or the other, or both? I am asking because they both seem to have similar settings, specifically, Noise Threshold.

Regards,
Bill

[dalomar_cg]

Re: DMC sampler vs Image sampler

The DMC sampler and the Image sampler are two completely separate functions, and therefore affect the rendering in two completely different ways. However, the final image HAS to go through BOTH of these settings, so just because they are separate and different doesn't mean that both don't have the ability to help with a render

With the image sampler, that's (more or less) determining how many samples to have per pixel. It doesn't make the samples that you take more accurate, but the more samples you have per pixel the smoother it will be, no matter what is behind that pixel. So that means really good image sampler settings will smooth out DOF, glossy materials, lights, and DMC GI...it will not affect the quality of IR and LC though as the quality of those solutions really aren't determined by image sampling (although it doesn't hurt )

DMC sampler everything has to deal with regardless. It sampler determines whether values meet the criteria of being "good enough" for the final rendering and whether any more samples are needed for a given parmeter or area. The DMC sampler will effectively make things more accurate. Again this is a very global setting with it affecting absolutely everything, with the exception of Fixed and Adaptive Subdivision AA methods...Adaptive DMC has its own separate noise threshold (which is why you might be getting a little confused between the two), and is essentially serves the same function as the noise threshold in the DMC sampler, but it allows for separate control of how that threshold affects AA.

Now the question comes when to use one over the other. That isn't a simple answer, but if you're trying to get better results from your IR and/or LC solutions, you're going to want to work with the DMC sampler. For things such as material smoothness, better image sampling settings may get the job done. I would consider DMC sampler a bit more of a fine tuning kind of adjustment...something that needs care and consideration. Using the Image sampler to get a better result is kind of an "every man's" way of getting it done...its easy to work with, doesn't require a whole lot of finesse, and gets things rolling 9 times out of 10. The real balancing act is how to get them both to work together with out both contributing to settings being overkill.

[Alexander Petrov]

Re: DMC sampler vs Image sampler

wonderfull explanation Damien I'm always use the same Noise Threshold in both samplers.
Also i did'nt use any AA filters, just adjust the Adaptive DMC Sampler min/max subdivs 1/100 and it gives me perfect aliased edges, without excessive render time of Cartmull Rom filter.

[BillyRaygun]

Re: DMC sampler vs Image sampler

Excellent information - thank you! Sorry for the slow response.