Exit portal and lights

[Pikadili89]

Hello guys! I am trying to make a high resolution interior render and I am having problems with noise that can't be cleaned up even after 60 hours of rendering. I was searching trough forums here for a solution and advices. I read somewhere on forums that I shouldn't have totaly white materials, instead that the whiteset materials should be 200,200,200 in RGB spectrum. I done that. Pibuz told me that pictures need to be 4000 to 5000 in width minimum so I could get artifact looking objects. So I done that too. I used Pathtracing method with MLT couse its double faster then Bidirectional PT with MLT (I read this somewhere on forums and tested it also). And there is still a lot of noise that I can't remove. So the main thing I read about interiors is that I should use exit portals, now theres two problems about that. First is that my sunlight is not passing trought them, only light of enviromental map, anyone knows why? (I am using env. map+sun obviusly ). The second problem is that I want that one part of the building can be seen from interior and since nothing is rendered behind exit portals thats a problem, even tho I could solve this problem easy in PS with two renders. Any comments and advises are appreciated. Thanks in advance!

[CTZn]

With exit portals one must use bidirectional path tracing, with or without MLT.

Speed should be evaluated against the visual result, since one sample do not have the same efficiency wether it was traced using PT or BPT, meaning that in some cases less samples per second can still lead to a faster convergence.

For mask creation there is the Alpha Render tracing method in the advanced SkIndigo render settings.

[Pikadili89]

Thanks for tips CTZn. That masking with alpha render looks promising, I will certanly try it out. And do you know why light of enviromental map goes trough exit portal and sunlight does not?

[CTZn]

And do you know why light of enviromental map goes trough exit portal and sunlight does not?

No I don't know why. Path Tracing is fast but in the other hand not as robust as bidirectional can be. Somehow exit portals seem to make light paths too complex for that method... don't ask me

[Pikadili89]

Thanks for info mate, now I used bidirectional with MLT and sunlight is included too. Since picture is 5000x2500 it will still need a lot of time to render, but with 10 hours of rendering the result is same as 20 hours of rendering when I used pathtracing with MLT with out exit portals on 4000x1950 picture.. Once again, thanks!

[CTZn]

You are welcome Pikadili, most Indigo users could have told you about that.