[zoppo]

Hi all, i really like MW but sometimes it drives me nuts.

Those are 1:1 details from a interior i made.
Behind the camera are big windows, then there are the ones at the left side, and a small one opposite the camera. Lighting by physical sky and sun light.

Material of the walls is a 204/204/204 white, lambertian with a small bump map and a second bsdf layer, weighted 10% with 90 roughness. Both ND3.
Glass is AGS.

The picture rendered quite a time on two x2-4800 and was merged to a mxi at sampling level 17.45

Long text - short question: WHY IS THERE SO MUCH NOISE AT SL17.45?
And what can i do to get rid of it?
IF there is any way besides buying another renderer? Point is - i like them so grainy but my clients don't.



Thanks for your help.

[JCAddy]

I suppose you could try removing anything "walls" behind the camera "not in view" and leave an open space.

That usually helps me out.

[Mihai]

Material of the walls is a 204/204/204 white, lambertian with a small bump map and a second bsdf layer, weighted 10% with 90 roughness.

Perhaps this is the answer to your question. How exactly is the wall material made? So the second layer doesn't use a texture as a weightmap, it's just 10% all over the material? This could lead to more overall noise, a better solution would be to make a weightmap with "specs" of white in them, to make reflective specs on the wall.

Try first just changing the wall material to only have that one lambert bsdf, and see if things improve. Don't go by benchmark alone when doing this, but compare instead noise levels at the same SL.

[def4d]

already answered, but don't search more : use 100% lambertian walls!

[zoppo]

thanks for your answers, a test is rendering atm.

but i got my doubts about the lambertian thing. 1st mverta said to never use lambetian as there nothing like that in the real world

- and 2nd: i'm sure i read a thread about one nice interior shot that was quite free of noise, and the guy used a 2 bsdf soultion for the walls ...

we'll see

[mverta]

A ton of people use Lambertian in all sorts of contexts and get great results. I personally never use them, because they're not physical. The only real-world materials that approach that sort of reflectance are highly specialized, like, space-exploration stuff as I recall. Some other materials are very close, but I just get better results by not deliberately starting my renders off with impossible values.

In the end, the values don't matter, the look does, so if you can get it with Lambertian, go for it. It's just not how I roll, and I don't personally recommend it.


_Mike

[zoppo]

well, thanks for your replies - i changed the wall mat to 1 layer lambertian. i have the feeling the rendering was a bit faster, but the noise didn't get better. SL 16.55



any other ideas? or are there images which just can't be done with mw?

btw - i will test it with hyperballads suggestion, i will do a test with a hdri and one with mihai's arch wall mat - even if it's 2 bsdf and not lambertian (and has strange nd settings - 1 & 2?? mihai?)

[DrMerman]

Hey zoppo.

From what I've gathered, interiors just take a LOT of time to clean up. There was a test posted here a while back by the Italian Maxwell guys that showed just how long it actually took to get a totally clean result (if I can find the post, I'll add it to this one.) But man, did it look GOOD

The two main ways that I've found of decreasing noise is to either use a HDR map for your lighting (the speed difference can be actually quite noticable,) or to use the old camera-flash method. By adding another light source to your scene you'll find that it clears alot faster.

I do agree with Mike on the lambertian walls thing, but I think that in the end, it comes down to taste.

Cheers,
Dr Merman

p.s Nice looking scene by the way

[andretto]

if you can live with it, try avoiding the physical sky and use large plane emitters and/or skydome... it will clean up way faster...

[4 HeRo]

At that S/L it should be alot cleaner then that.
if its possilbe could you sent me the scene and i'll take a look see if I can help, 3D Max if poss or as an mxs would be fine, I only need the room so no fixes and fitting will ok.

Other then that I not sure what esle to say would help.

John

[JCAddy]

Try removing the walls behind the camera

[zoppo]

Try removing the walls behind the camera

i will, as i wrote above - just got some other things to do right now

@DrMerman: thanks for the compliment and i will try hdri and maybe some cam light. but i think it may - well, "bias" the picture. i wanted a pic of the room without artifical lighting and i'd love it if mw could handle that.

@andretto: i read about the sky dome thing - it's just ... it doesn't have the light quality the physical sky has. i might try it over the weekend. and i read another thread where somebody tested sun vs large emitter - and the sun was faster. but it was a scene with direct light as i remember.

@4 HeRo:

At that S/L it should be alot cleaner then that.

exactly what i think - i'm working with c4d, so there's only a mxs. what do you mean by "I only need the room so no fixes and fitting". what are fixes and fittings?

[Tora_2097]

There is definitely something wrong with your scene. An interior scene that simple with lambertian wall materials should be MUCH cleaner at SP level 17.

http://forums.cgsociety.org/showthread.php?t=390280

All at around SP level 16-18, rendered in 12 hours on a Dual XEON 3.2. Lambert walls, glossy floor, sky/sunsystem.
Do you mind posting a screenshot of your scene layout and your materials for the floor and walls?

Regards,

Tora

[mverta]

I'd try temporarily turning the floor into a Lambertian, just to test. That glossy might be a large culprit. It's not a coating, is it?

_Mike

[zoppo]

thanks for your answers.

the floor has no coating, just 2 bsdf. there is a lot of stuff around (see below).
cooking atm: same scene, all stuff not seen by the cam removed, walls mat mihai's arch wall.mxm ans i changed the sun position so it hits the room more. it's at 14.85 up to now but it's not really looking different noise wise.

floor:



scene and walls:


i will post more tonight.