Noise

[Numse]

I have some problems with noise in my render, and rendertime. I need to get rid of the noise in the image. The render has not the quality I want. And it be helpfull to get a lower rendertime to.

Here is the image and my settings.

http://www.digitalartist.biz/Projekt/13.jpg

http://www.digitalartist.biz/Projekt/vray1.jpg

[flipside]

Switch to 1/4 for your AA settings. The noise is coming from your glossy materials, you need to increase the subdivs of the glossies instead of turning up your AA settings. High quality is from 20-40.

Do you have area lights in your scene? I guess you do. Also here, increase subdivs of the light instead of upping AA settings. I would suggest values between 15-30.

The best way to deal with the noise is to leave it there. Nobody will notice it anyaway, only vray geeks like us.

Don't expect to render a scene full of glossies (and maybe are lights) to render fast if you want no noise at all...

If you do use area lights (without the store with ir map option!), you can lower your IR map settings, because your shadows will be raytraced for most part of the image anyways. For the resolution you posted, I would say use min/max=-4/-1 of -5/-2, with density based lookup method.

Besides you noise, I think there is something wrong in your lighting setup. You should never use GI multipliers higher than 1. Increase your lights and environment light.

[Numse]

The render doesn´t take that long, it´s the GI-calculations thats timeconsuming. So I´ll try higher glossy subdivs. and lower IR map settings, as you said.

I use one area light yes. It´s nothing wrong with my lighting setup, I use one light sorce, the sun. And to get the right lighting in my scene I need higher GI multiplyers. If I use higher light multiplyer the direkt light is to strong.

why can I use lower IR settings btw? When is there a need to use higher settings? Is there big differences in quality?

Thanks for the reply.

[DaForce]

39hours for that?!??! geezus thats way too long!!!
What sort of computer do you have? 486?

Nice looking render tho

Try putting your GI multipliers back to 1 and 1 and then play with the Color mapping a little more.

[flipside]

You can use lower IR map settings, because you are using an area light. This light will already generate 70% of the light in your scene (and it is direct light, not GI, so it's raytraced and always perfect). The other 30% is GI light (first bounce after the direct light hits a surface, and then secondary bounces). Because this GI light will not be very dominant, you can use lower IR map settings.

The higher the resolution, the lower the min max settings should be. For example if you did a test render at 640*480 and you found the GI light detailed enough with for example -4/-1, and you then going to render high resolution at 1280*960, you can lower the min max to -5/-2. This will give you the exact same GI detail as in the test render. Everytime you double the resolution, you can lower both min and max with 1.

The presets of IR map are good for resolutions of 640 to 800px. So using medium preset on a 3000px wide image is not a good idea...

Like daforce said, try using GI multipliers of 1.0 and adjust lighting in other ways with color mapping or lights intensity. That can speed up rendering too (if you would use the lightcache for secondary bounces, never use multiplier higher then 1!)

A real picture of a room like that would have burned out areas on the floor. I guess that's a personal opinion, but I don't like the look of exponential color mapping. The exterior should definately be burned out.

[Numse]

DaForce:
Yeah it´s a bit long.
P4 2600, 2GB DDR.

flipside:
Ok, I´ll try lower IR settings. And I´ll play around with the color mapping.

Here is an old color mapping test:


I don´t agree with you about burned out areas. The sun is set low so it´s not that strong, and therefor it shouldn´t be any burned out areas.


Thanks for the replys guys, it´s very helpfull. I´ll see if I can do some testrenders and show you the results soon.

[DaForce]

The last one of those IMO is the best looking. Is that with GI multipliers at 1?

[Numse]

Nope, primary around 2 and secondary 1.
I´m testing 1, 1 and different colormapping with brighter light right now. And I´m also testing GI with and without glas in the scene, to see if there is any difference.

[Numse]

I´m finished with the test and the result is quite interesting.
I have lowered the IR settings to very low and both GI multiplyers to 1. To get the same effect as with high primary bounces multiplyer I used a high light multiplyer and 1.7 dark- and 0.5 light multiplyer in the color mapping rollout.

Look at the difference in time and scene lighting for the render with glass and the one without.

http://www.digitalartist.biz/Projekt/Glastest.jpg

[flipside]

You could render imap without the glass and reuse it with glass.

It's taking so long because of the GI caustics that need to be computed also. I guess that especially the window glass will increase rendertimes a lot.

Using lightcache for second bounce can also speed up things a lot. Fot testing use 500 subdivs, turn off 'store direct light', turn off the filter and turn on the pre filter. Set sample size to 0.01. For higher quality increase subdivs to 1000-1500.

Maybe you can even disable GI for the glass? Don't know if that will work.

[flipside]

hey numse,

I did some tests. Go to vrayproperties for all your glass panels, and turn off 'visible to GI'. Also disable shadow casting in the max object properties for the glass panels.

That way, your panels will not produce refractive GI caustics, but still let all the light pass trough, resulting in faster rendertimes and much more light entering the room. No need for saving and reusing ir maps.

wouter

[Numse]

Tnx, I´ll try that right away.

I´m rendering a test right now with the IR and subdiv. settings you suggested and it is a lot faster and have better result with less noise.

[Numse]

Here is the testrender:

http://www.digitalartist.biz/Projekt/16.jpg

Rendertime is down and the quality is good. Less noise anyway.

The reflections on the floor is off, very strange.. the floor doesn´t look good at all, not like in the first render in this thread. And I don´t know why, is it becouse I changed the GI multiplyers and the color mapping multiplyers?

I believe my first method with high primary GI multiplyer and low light multiplyer is better than this one.. what do you think?

[percydaman]

hey not bad. personally I think your overdoing it on the fog color with the glass though. It needs to be a little bit more subtle.

Also you need to please email chaos for access to the members forum. This portion of the forum is for the demo version. It may seem a little anal retentive but alot of people come here asking for help who have cracked versions....

[flipside]

That's the problem of color mapping. In fact, you should leave both multipliers to the same number. Otherwise you lighten up the dark areas, and darken the light areas, giving strange results. (making your dark areas as light as your light areas). Does that make any sense

I'm making some test, will post them later today