مشکل با v-ray HDRI

men · Nov 1, 2009

کسی تا حالا با این مشکل برخورد کرده؟
تصویر بالارو ببینید.این که نورا اینطور پخش می یوفته رو زمین و اینا

Tutorial overview:Using HDRI for lighting will result many times in a lot of splotches and blurry shadows. Especially with high resolution HDRI maps containing a lot of contrast and/or small light sources, this can become a big issue.
This tutorials covers a quick and easy fix for the problem, without increasing rendertime too much, and without resizing or blurring the HDRI map.
The tutorial is in html format. After downloading, simply unzip the files and open the html page that carries the name of the tutorial.
Tutorial Statistics:Words: 1084
Characters (no spaces): 4152
Vray 1.5SP3 for 3dsMax 2009
Price: €5

DejArch · Nov 1, 2009

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I used to try to use free HDRIs found on various sites for GI lighting, but the effect was invariably cr*p, very very splotchy results like your aimge. I realised that simple fake "studio" HDRIs with a more or less black background and 1, 2 or 3 very blurred light sources rendered well, but any HDRIs which were highly detailed (made from actual spherical panoramic photographs) just don't work. They're excellent for backgrounds and reflections, but aren't very useful when it comes to lighting. As Thom said, you can still use these HDRIs for GI by reducing them in size- in fact I've found you can reduce them down to just 200 x 100 px without any additional blur and they will produce good, clean results.

The first splotchy render below was rendered using a very high quality 6000 x 3000 px spherical HDRI like the one above.
The second image was rendered with exactly the same settings and the same HDRI, but reduced in size to just 200 x 100 px in Photoshop first. The remarkable thing is that even though the splotches are pretty much gone, the shadows are still as sharp as in the first one. Oh, and another thing- the original size HDRI was 51.9Mb- the tiny version I used to do the second render is just 64.7Kb! In other words, when it comes to HDRIs for backgrounds and reflections bigger is better, but for lighting they can (and often should) be tiny.