I have a problem with big white surfaces, I get splotches in highres images. it’s not visible at lower resolutions. how can I reduce the effect to get cleaner renders? the rendertime is a problem and must be as short as possible. the imagesize is about 6000px and rendertime 6 hours.
the min/max value controls the ir map resolution, i.e. the number of samples and the size of the splotchiness…higher max values provide small splotches
the hsph subdivs controls the sample quality, so the higher this value the smaller the variation in noise. 80 is what i consider very high…i use 20 for 95% of scenes and have zero noise. cutting down to 20 could reduce ir map calculation to a fraction of the time.
the inter samples controls how much the variations in splotches are blurred together. the default value of 20 often is too low (unless you have extremely high ir map resolution or hsph) and you can raise it to 100 or so to remove all noise for a relatively small increase in render time
I think you should read more in the samples, Maxxer.
Also read the post further down which has 2 links.
HDR, Domelight, or simple light source, the way the IRMap is calculated remains constant, as the benefits of lowering min rate and using a high scissor between min and max.
80 Hsubdivs are heritage of when HDRs were used without importance sampling, or to be used when secondaries are set to qmc and those do a poor job.
Try, and i am SURE that noise will go away.
I have not had it since ages, with this simple trick.