[Q2]

Hi guys

Well here we are again, the good old maxwell noise topic.

Ok, here is what I had to deal with:

I have a really huge scene of a car dealership which needs to be rendered. The interior shot is looking outwards and the exterior shot is facing towards a illuminated sales room, located inside the building. Now, I am using a high res VHDRI from "Hyperfocal Skies" to get a great moody exterior lighting setup. On the inside of my building I have about 60 down lights which have about 400 watts each, geometry joined, and the emitter value is 24000 watts. So far so good. My problems start when I start to mix Emitter lights with my VHDRI and/or physical lighting in Studio. If I turn the emitters off and render the outside view, everything is just perfect, the light illuminates the scenery just fine. The same happens when I only switch on my emitter lights in the large sales area.

But as soon as I turn on just one emitter, even with lets say just 1 watt of power, somewhere in the building, I get noise ALL over the place. And that stuff hangs on like rock snot!

My materials are all double checked and none of my white wall materials have a value more than 220 and all have roughness value of 95. I have no SSS materials in my scene and all my glass is AGS or hidden in the perspectives where I don't see it anyways.

Again, everything renders fine in one of these settings:
VHDRI/Physical Sky = Perfect
Emitters= Perfect
A combination with Emitters and VHDRI/Physical Sky= PURE HELL

The thing I came up with now is to use the Physical Sky settings and my Skydome/Sun as lighting not used in my IBL Refraction channel to get at least some sunlight and emitters to work together. The result is not very good either, the look and feel is quite different but I need to have sunlight shadows from trees and emitters lighting my scene on the inside. I also tried to make a little artificial sun but that gave a really creepy light so I dissed that, too. And I cranked up my resolution to something crazy like 10000x4000px to scale it down later to get less noise. My client whats to have a 4800 px picture in the end which is quite normal, since they want to print it out rather large.

Sorry that I can't post a picture but I have signed the "special paper"

Does anyone have an idea what else could be done? Any magic settings I have missed? ANY THING?

Cheers Q!

[Half Life]

Try boosting the power of all your emitters except the IBL (before your render) and then reduce them to the level you want with multilight/photoshop plugin.

I think the issue is the relative power between the light sources is too severe... I guess you could go the other way and reduce the Intensity of the IBL -- but whatever you change you need to do it before you go to render and then adjust it back up/down in Multilight during/after render.

Best,
Jason.

[Q2]

Hi Jason...

Jepp, I went down that road also, but no luck. Noise like a winters snowstorm....

Cheers

Q!

[Half Life]

Are you using IES? Color Multilight?

Best,
Jason.

[Q2]

Nah, just a normal emitter with 230/255 white with normal multilight settings. I tried IES also but that didn't make a difference.

Q!

[Half Life]

Well, not being able to see it makes it hard to figure out -- does the noise still happen if you don't use multilight?

Best,
Jason.

[Q2]

Yes, still there even without multi light. I am really sorry I can't show anything. When the renderings are through, they are running right now, I will make a little test scene and post the results!


Q!

[polynurb]

sorry to ask again.. are you sure all your emitters are joined together?

if i get you right your hdri is causing the noise.. so some emitters must be stealing the processing power.

i had some problems like this before.. but its some 2.x versions ago. for me it solved with joining all the emitters.

alternatively you could try to use mxi emitting texture insted of direct emitters. maybe this combination works better for the moment.

[Q2]

hi polynurb

yes, the emitters are all joined, definitely! And I don't think the VHDRI is causing the problem cause the combination of emitters and physical sky is also giving me the same issues.

Somehow I believe the simple fact that I am mixing emitter lighting with some sort of exterior lighting gets the render engine confused and it shows tons of noise.

I will give your idea with the mxi emitting texture a go as soon as these renderings are through.

Thanks for the help!!!!!!!


Cheers
Q!

[polynurb]

no problem... hope you get it solved.

this is a thread about the same issue.. a bit long but informative.

http://www.maxwellrender.com/forum/view ... ly+shadows

usually this only happens when emitters are very much out of balance either in number or in power.
but who knows maybe some things changed here with 2.5.

btw. i also use these VHDRIs they rock...

daniel

[Q2]

usually this only happens when emitters are very much out of balance either in number or in power.

Well Daniel, you hit the spot! I just found out that the VHDRI' in my Refraction Channel had a value of 15! All other channels had a value of one. Changed it to 1 and did a test render and - voilla- everything rendes the way it should!

Somehow I overlooked this setting and the noise kept creeping in!

Thanks again for you support and advise!

Cheers from France

Q!

Yes, VHDRI rock..... I love'm!

[Brendan Sharp]

I've just read this topic and the 5 pages linked by polynurb and still can't figure out why I am still getting the results I am. I'm trying absolutely everything- I am not however using HDRI's just physical sky or sky dome- see here this post for my images. (still just setting up a site by the way but will not continue with model untill I can resolve this issue):

http://www.maxwellrender.com/forum/view ... 05&t=35972

hey Q2 what do you mean by "I just found out that the VHDRI' in my Refraction Channel had a value of 15! All other channels had a value of one."

any chance of a screen shot. where would this be apparent when just using physical sky/skydome???

anyone.....

[Q2]

Hi Brendan, have a look here....


It was a simple mistake and I overlooked it twice. Have a look at the "Refraction" settings. See the Intensity slider at 15, that would mean that the sun in this channel would be 15 times brighter than the normal sun. The problem was that the render engine does have a too wide of a emitter power range and then it starts to get really grainy.

If you want to send me your file I would have a look at it and give it a shot trying to solve the problem!

Cheers

Q!