Guest nazcaLine Posted March 25, 2007 Share Posted March 25, 2007 i am making some draft renders and i got these grain all over the white surfaces. i get grain when i render with low presets but this time is too much, and only on the white . my settings: irr map in very low preset, 30-20, light cache 300 samples, big vray lights in windows. any help will be appreciated, thanks. Eduardo. Link to comment Share on other sites More sharing options...
batteryoperatedlettuce Posted March 25, 2007 Share Posted March 25, 2007 Is all the white stuff using the same material? What are the material settings? Link to comment Share on other sites More sharing options...
ApeiNe Posted March 25, 2007 Share Posted March 25, 2007 LC is really low I think... Also increase VrayShadows samples Link to comment Share on other sites More sharing options...
batteryoperatedlettuce Posted March 25, 2007 Share Posted March 25, 2007 I tried recreating your problem with my testing room. The LC samples seemed to have a big effect as did the shadow samples. Also the QMCsampler settings when pushed down too low had the same effect on the test rendering. I'm not an expert (I've been doing vray interiors for less than a fortnight) but I recon you need to look at the QMC sampler settings. The default values should be giving reasonable results. I'm looking for confirmation on my guesses rather than offering advice. Link to comment Share on other sites More sharing options...
ApeiNe Posted March 25, 2007 Share Posted March 25, 2007 I tried recreating your problem with my testing room. The LC samples seemed to have a big effect as did the shadow samples. Also the QMCsampler settings when pushed down too low had the same effect on the test rendering. I'm not an expert (I've been doing vray interiors for less than a fortnight) but I recon you need to look at the QMC sampler settings. The default values should be giving reasonable results. I'm looking for confirmation on my guesses rather than offering advice. I think the LC is the first problem, if you're using QMC AA it can be a solution, but adapt subdivs don't need to increase so much QMC sampler i think so Link to comment Share on other sites More sharing options...
Guest nazcaLine Posted March 25, 2007 Share Posted March 25, 2007 i'm using vray 1.5. the qmc sampler is on default, 0.01 , and yes all have the same material. i'll try rising the light cache samples, i always keep them low for test renders. let's see what happens if i increase the vray shadow samples... Link to comment Share on other sites More sharing options...
Guest nazcaLine Posted March 25, 2007 Share Posted March 25, 2007 i increased lc to 700 and the shadow subdv from 8 to 12, and it didn't work much... right now rendering with 300 lc down again, and qmc sampler to 0.004. ... Link to comment Share on other sites More sharing options...
Crazy Homeless Guy Posted March 25, 2007 Share Posted March 25, 2007 what happens if you bump the LC up to 1200 to 1400 or so? Link to comment Share on other sites More sharing options...
Guest nazcaLine Posted March 25, 2007 Share Posted March 25, 2007 look at this. i checked "store with irradiance map" in the light's panel and the noise dissapeared. the render time was very short also. of course, you lose some detail, since the shadows are very soft. but it works. it's not recommended i know, but since my pc is very poor (1.6 ghz processor, 750 mb ram) it is really useful. right now i'm rendering a high resolution image with high irr map settings (-3,-1,50-20) and 1000 lc samples. i ncreased also the shadow subdv to 16. but now i have another problem; the floor is not reflecting anything, it has a reflection with .7 glossiness. could it be because i checked "use lc to trace glossy rays" in the light cache rollout??? Link to comment Share on other sites More sharing options...
ApeiNe Posted March 26, 2007 Share Posted March 26, 2007 so i think it definatly comes from your vrayshadows sample, just for a try, boost it to 24 or 32, maybe the grain will disappear, cause actually if you're using a long vraylight panel it gives you area shadows , maybe trying to put more than just one big vraylight on the window could be put 1 light for each glass panel. Link to comment Share on other sites More sharing options...
Christopher Nichols Posted March 27, 2007 Share Posted March 27, 2007 look at this. i checked "store with irradiance map" in the light's panel and the noise dissapeared. the render time was very short also. of course, you lose some detail, since the shadows are very soft. but it works. it's not recommended i know, but since my pc is very poor (1.6 ghz processor, 750 mb ram) it is really useful. right now i'm rendering a high resolution image with high irr map settings (-3,-1,50-20) and 1000 lc samples. i ncreased also the shadow subdv to 16. but now i have another problem; the floor is not reflecting anything, it has a reflection with .7 glossiness. could it be because i checked "use lc to trace glossy rays" in the light cache rollout??? Basically all this is saying is that your noise is coming from specular rays since the side effect of store with IR map is that it only shoots diffuse rays. Hence the lack of reflections (specular). This has nothing to do with shadows. Therefore, it appears you have three choices. Either remove all specular (reflection) from your wall materials (easiest), or increase the subdivs on the reflection to something like 24 or higher (better), or used a more robust AA method such as QMC AA at a high level (best). Personally I like the third solution... Link to comment Share on other sites More sharing options...
Guest nazcaLine Posted March 27, 2007 Share Posted March 27, 2007 thanks for your answer christopher. the walls have no specular, i mean is just a white color with no reflect, is that simple. about the antialiasing, i'll give it a try. does it mean that i'll have to increase ( i mean reduce ) the qmc sampler noise? oh, and i have another thread with a problem about color mapping...please check it out... Link to comment Share on other sites More sharing options...
Christopher Nichols Posted March 27, 2007 Share Posted March 27, 2007 thanks for your answer christopher. the walls have no specular, i mean is just a white color with no reflect, is that simple. about the antialiasing, i'll give it a try. does it mean that i'll have to increase ( i mean reduce ) the qmc sampler noise? oh, and i have another thread with a problem about color mapping...please check it out... Well something is causing those specs, and I really don't think it is the shadows. A good way to debug is to render out the elements (spec, reflection, diffuse, GI) and see where you see the artifacts. That will give you the answer. Increase the QMC will only get you so far with noise thresh. You need to bump up the Max value to something like 16. Link to comment Share on other sites More sharing options...
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