10-08-2020, 06:24 AM
Quote:I noticed that samples is set to 150
Well done ! I raised the value to 150 just to see whether it changes something about the smothness of shadows, then I forgot to put it down afterwards. As I set the light sampling grid to 6x6 in Povray, the fair comparison is obtained with 36 samples in Yafaray, and then Yafaray is a little bit faster than Povray, using similar quality settings. That clearly explains the strong speed difference I have observed !
By the way, it's still too bad that Yafaray doesn't have an adaptive mechanism for shadow rays : if you send, say, 5 shadow rays to an area light (1 at each corner + 1 at the center) and all 5 rays return the same value, it's pretty much sure that the whole source is visible from the corresponding location, so sending the remaining rays is more or less useless. Of course, there may be some exceptions (very small obstructing objects can be missed with an adaptive process) but the benefits are usually much higher than the drawbacks. Adaptive sampling can be unchecked in Povray, so you can choose between both options. I really would like to have something equivalent in Yafaray.
Just a word about the saturation circles that appear on the walls : I could remove them by reducing the "diffuse reflection" parameter from 0.5 to 0.25, so the illumination gradient is still present but without saturation. Anyway the "good" solution (I'm always too lazy to use it, though) to avoid such over-exposed and/or under-exposed areas in the final image, would be to generate the final image as an HDR or EXR image, and then perform an adaptive 8-bit tone mapping afterwards. The "Radiance" software provides some standalone tools for this step, and most recent image processing softwares (Photoshop, Gimp) also include such a tone mapping process. It might be interesting to investigate this option a bit more, for scenes with complex illumination scenarios.
>>> sciroccorics <<<