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rendering problem... gives grains


yogeshwagh
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hi to all,

please help about my problem, my scene is of courtroom , it is having a wood mateial everywhere, when i am rendering my scene it shows me some grains in my output. My settings are as follows:

Primary engine : Irradiance Map

settings : high animation settings with four passes and others are on default.

 

secondary Engine : Lightcache

Subdivs : 800

samples : 5

Pre filter : 20

And all other are by default.

 

Environment settings : multi: .6 with HDRI map.

 

And render image size is : 1920 X 1920 Pixels

 

Courtroom is having 5 windows on the first side and another 5 windows on the other side. i have taken vray light for each window to get the feel of sunlight comes in.

 

Vray light parameters are as follows :

Invisible off

Multiplier : 20

Smooth shadows on

Store with irradiance is on

 

Total render time is also taken on high, is about to 5 hrs per frame .

So please help me , and give me the solution.

 

 

thanks

Yogesh

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Well you might just need to raise your HSph sub and Interp samp settings, but like its been said, we need to see it, it could be a material thing, also are you saving and reusing your IRR. maps and lightcache maps, that will certianly speed things up...

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Firstly, I would change your lightcache settings just slightly. Raising it from 800 to 1000 or so will probably help the noise issue a little. You know your scene better than me but in most cases I would guess that 4 passes would be enough and you probably wouldnt need to prefilter. Anyway that will help reduce render times not so much the noise.

 

You can also go into your QMC sampler and reduce noise there. Set the noise threshold from 0.005 to 0.004. This will reduce your noise slightly, but slow rendering time to compensate. keep going down by one until you feel you have noise reduced anough and still at a comfortable render time.

 

What can also help is if you change the other values in your qmc from 8 to 16 and from 1 to 4. This will SIGNIFICANTLY increase your rendertimes though as its basically multiplying some of your other settings etc.

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Well thats going to be a very nice render when its done, I would however think with all that natural light and being that you have all the lights in the room on, that it would be alot brighter in there...

 

Did any of those adjustments have any effect at all ??

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Well thats going to be a very nice render when its done, I would however think with all that natural light and being that you have all the lights in the room on, that it would be alot brighter in there...

 

Did any of those adjustments have any effect at all ??

 

hi,

thanks for reply, I have used the vray lights for each window from outside, there is no light in the interior of this room. can i use the lighting in the interior room other than the outside? i think it will affect a little bit to our reference. but its ok, i want some help can u please tell me how can i lit this room.?

i have using uvw map for each of these surfaces if we use uvw unwrap will it be work for grains?

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It really looks like those chanelaires are on...to me anyway, but if not thats ok, you can raise the multipliers on your vray lights to give more illumination to the room, what are your material settings for the wood, you might just need to raise the subdv. in the reflection...

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It really looks like those chanelaires are on...to me anyway, but if not thats ok, you can raise the multipliers on your vray lights to give more illumination to the room, what are your material settings for the wood, you might just need to raise the subdv. in the reflection...

 

thanks for your reply,

It really looks like those chanelaires are on? means can u please tell me what do you exactly mean. my material settings are having subdivs of 32 for the reflection.

Can i use the Vraylightmaterial from outside instead of vraylights? and do some lighting in the interior for matching the lightsource is comes from outside?

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sorry, that means it looks like those lights hanging from the ceiling are lit...

I think your subdv might be too high actually, maybe 16 would be enough, if its not getting rid of the grain at 32 subdv then I don't think that's the problem, did you try raising your HSph sub and Interp samp settings ??

I think I would stay with the vray lights, they give you more control, but you could add a vray light sphere to the room as an area light, it doesn't seem like you are getting any indirect light from the GI...

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sorry, that means it looks like those lights hanging from the ceiling are lit...

I think your subdv might be too high actually, maybe 16 would be enough, if its not getting rid of the grain at 32 subdv then I don't think that's the problem, did you try raising your HSph sub and Interp samp settings ??

I think I would stay with the vray lights, they give you more control, but you could add a vray light sphere to the room as an area light, it doesn't seem like you are getting any indirect light from the GI...

 

hi, thanks for your reply, My Hsph . subdivs are 50 and interpolation smpls. are 30. if raise them will it be affect to my render time? now it takes 7 hours per frame with irradiance calculations for 4 passes. and lightcache passes.

My irradiance and lightcache are calculated within one hour, but when it starts rendering image it takes more time, can you please help me , why it happens like this?

the top lights are having only a white material

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Well for starters, save your IRR. maps and your lightcache maps and reuse them, that will take away that hour of calculation, also in the light cache settings, use lightcache for glossy rays, check that...

 

The reason it takes so long to render is because almost everything in the room has glossy reflections...

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Well for starters, save your IRR. maps and your lightcache maps and reuse them, that will take away that hour of calculation, also in the light cache settings, use lightcache for glossy rays, check that...

 

The reason it takes so long to render is because almost everything in the room has glossy reflections...

 

thanks for your reply sir,

yeah thats true it takes time to render because of reflections. but about the grains, is there any problem with my material i will post you my material for reference. please check it.

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Not so much because of reflections, but because of glossy reflections, they are very expensive in terms of speed, I just did and experiment with glossy reflections, and if you check "use light cache for glossy rays" in the light cache section, it should decrease your render times by 1/2, at least thats the way it worked for me, it took 1 min. to render a scene with glossy reflections, and when I checked "use light cache for glossy rays" the render took 30 sec.

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Oh, and I meant I wanted to see a peice of the rendering, the picture here is too small to see the problem, I need a closeup...

 

oh, sorry, i meant you want to see the material , please check this attachment i have attached the closeup of the grainy wood material

 

 

thanks

yogesh

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Ok, so try this, render at 640x480 just so we don't have to wait all night, bring the material reflection subdv. down to 16, check your "use light cache for glossy rays", and raise the Hsph subdv. to 70, and your vray light "samples"

to 16, after its done, save you IRR. map and your Light cache map, you can reuse it for your larger render...

 

Then post the results...don't worry, we'll figure this out...

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Ok, so try this, render at 640x480 just so we don't have to wait all night, bring the material reflection subdv. down to 16, check your "use light cache for glossy rays", and raise the Hsph subdv. to 70, and your vray light "samples"

to 16, after its done, save you IRR. map and your Light cache map, you can reuse it for your larger render...

 

Then post the results...don't worry, we'll figure this out...

 

hi,

thanks for your support and helping me to finding out the solution, i will make the settings as you told, but if i use store with irradiance map check box on and smooth shadows on for vraylight will it be effect on the rendertime?

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Guest nazcaLine

very nice modelling!!!

 

what antialiaser are you using?? probably you're using adaptive.when you have a lot of glossy reflections it's much better to use the simple two-level antialiaser (i have the 1.03 version of vray, i think this antialiaser changed its name in other versions) i made a comparison and the diference is noticeable.

give it a try!!!

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very nice modelling!!!

 

what antialiaser are you using?? probably you're using adaptive.when you have a lot of glossy reflections it's much better to use the simple two-level antialiaser (i have the 1.03 version of vray, i think this antialiaser changed its name in other versions) i made a comparison and the diference is noticeable.

give it a try!!!

 

thanks , i will try it

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hi to all,

I post you the image with two diffrent wood textures and in sizes also. but when it renders it gives me some grainy specular and diffuse too. so please help me about it. how can i get the smooth feel to my material .

 

My Material Settings are as follows :

High glossiness :0.75

Refl. glossiness : 0.75

Reflection value :20 RGB

falloff map with the fersenal reflection to the reflection map.

 

 

Primary engine : Irradiance Map

settings : high animation settings with four passes and others are on default.

 

secondary Engine : Lightcache

Subdivs : 800

samples : 5

Pre filter : 20

And all other are by default.

 

Environment Reflection checbox is on multiplier is 1

Environment GI Multimplier is 1

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