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Any know what is causing this artifact?


TomasEsperanza
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Anomoly.jpg

 

The splotchiness in the mirrors looks like a GI issue to me. I am perplexed though; why does it appear only in the Mirrors?

 

The GI settings were pretty high; Light Cache: High 2000+, Irradiance Map: 200

 

I'm thinking it's to do with the mirror material perhaps? Does it need a higher "Max depth" value?

 

Or perhaps there are not enough photons from the light sources in the scene?

 

Anyone who can save doing loads of test renders on this is a star! :)

 

 

ps: just noticed it's actually very evident on the reflection of the vase too.

Edited by TomasEsperanza
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try raising the reflection subdivs value from default 8 to about 24.

 

Yup - reflect subdivs were at 64, (with glossiness at 0.99). The fill lights (a V-RaySun through the door opening, and a dome light with an hdri) had subdivs at 512. The Global Subdiv Multipler was at 4. But those spotlights are plain Max lights and they provide most of the illumination, (do they do photon emissions?)

 

Perhaps the problem was with the dark scene?

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Are you using vray 3? I'm using 2.4 so the settings might be different but it looks like a GI problem. Light cache seems low to me, my animation low res preview setting is at 250. Try bumping it up to 500 and see if it makes any difference. Also I'm not sure where your getting the 2500 from on your irradiance map? Again it might be the new version is different.

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Are you using vray 3? I'm using 2.4 so the settings might be different but it looks like a GI problem. Light cache seems low to me, my animation low res preview setting is at 250. Try bumping it up to 500 and see if it makes any difference. Also I'm not sure where your getting the 2500 from on your irradiance map? Again it might be the new version is different.

 

Nah, soz mate I'm just chattin shit - I meant the other way around. Yeah 2.4 also. (Lol those would be crap settings!)

 

..Still maybe because it's a dark enclosed space it does need even more GI....

Edited by TomasEsperanza
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lol no worries. I would put it down to not getting enough light into the corners behind the camera. you could make a vray skylight portal in the door to chuck a bit more in, or maybe on your spotlights extend the falloff field to get more light into those back corners...

 

Thanks James, that sounds like good advice.

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Easy juz add sum more lights in d scene either it is plan window light aur door light.. juz dnt increase the Gi value .. all uh have to do is increase bounces in the scene .. may be the default value is 100.. jz try to increase dat value to 150. N main thing juz check ur unit setup coz dis is more important for the light in vray aur what ever engine uh using for rendering..

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I don't think this is as simple as GI settings because it is only seen in reflections. And what you are seeing is not 'poor sample blending' it is the samples themselves. It's pre-pass stuff. WTF?

 

I did an animation a few years ago where That happened. It was a nice piece, except that issue ruins it for me. But it was a super-fast competition type project, so just getting anything to show was enough. Asking about this on the Vray for Cinema4D forum didn't get me anywhere. Pointing out any issue with vray usually results in "well you obviously have wrong settings, your cucumber weight is all wrong and you need more walrus belching and clearly that will solve the samples/bias/multiplier/whatever". Then they suggest BruteForce.

 

https://vimeo.com/64253956

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I looked it up, this was the only direct answer to why my reflections were showing GI samples. Note that this was four years ago, things have changed in vray since:

 

the reflections is most likely that you had on LC glossy interpolation, but a very low lc setting. its a usefull tool for stills, better dont use that for animation also.
Stefan Laub of vray4c4d

 

The thing is I was pre-caching the LC of an IR/LC camera animation.

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To me this is low Gi values, if you notice in all the other elements in the scene there is barely any shadow contact, and I am not suggesting to add AO but maybe detail enhancement. Those artifacts are typical of to much interpolation or samples to far from each other.

as mentioned by Ernest, turn of LC glossy interpolation, reduce your LC radius and increase samples, and use Irr Medium or High.

Increase the number of samples also may help.

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