View Full Version : maya 2011 sun&sky render passes problems

08 August 2011, 10:48 AM
Hey guys,

i know there are some threads about that topic but at the end, you couldn't get a real statement out of it.So my question is, is it possible to get out correct passes?

My problem is that the main render window looks good.
But the passes are all blown out.
I have used a photographic exposure ( gamma 1.0 ) control on my cam and it seems that
all passes are getting nothing from that node. Is there an option to pass the exposure node
also to the render passes ? Also when i just render them out at 32Bit and load them
into photoshop and set the exposure to 0,454 i don't get the same result as in the render view.
I can remember that it "worked" in earlier versions. Can someone please shed some light
into this never ending "topic"



08 August 2011, 11:00 AM
gamma should be 2,2

08 August 2011, 11:17 AM
Can you elaborate a bit more?

So is it possible to add an exposure control to hte passes ?

I have also used gamma 2.2. But still the same problem.
My beauty pass as an example is not looking the same as the render view.
Although i use the 0,454 gamma in photoshop cs5

08 August 2011, 11:23 AM
I have switched to exr ( used tiff before ) and it seems to work, but still i have to test it.
Does anyone got the same problems?



08 August 2011, 12:47 PM
nope, still every render layer / passes is totally blown out.

any hints are appreciated.



08 August 2011, 02:04 PM
As far as I know, it is not possible to render mentalray passes with exposure adjustments. You could adjust your lighting and reduce your over all illumination, or do the exposure adjustment in post after you combine the passes.


08 August 2011, 02:21 PM
Thanks for the heads up David.

It's a shame that it's not working right with sun & sky.
Of course i can resetup my lighting but as you know
i'm quite sure that the result will not look as good as with the exposure.


08 August 2011, 07:31 AM
It's a shame that it's not working right with sun & sky.

No, this is the correct way it should work. Your passes will not get tonemapped by the lens shader, only the master beauty.

This is because mental ray assumes (correctly) that passes will be adjusted in post and should always be linear.

Maya should not be used for color work, that should be reserved for post applications designed for it so you have better control and flexibility instead of trying to make a 3d package do it for you resulting in needless frustration and murders.

08 August 2011, 08:54 AM
Hi David,

i'm totally with you.
Buit the fact is, that i can not get an adequate result when using the passes in post.
It's really looking "wrong" in my view, or let me better say, it's just not looking good.

That's the problem. On the other side, in 3dsmax the passes looks different and
there, i can almost get the same result as the masterbeauty - and that's odd.

Also what is totally strange, and that is what i don't understand.
By only setting the gamma in Photoshop to 0,454 i have reached nothing.
Normally that should "fix" 90% of the blown out look, but it doesn't work.
And that's what i don't understand...



08 August 2011, 09:35 AM
If I recall, there's some sort of bug that makes the outputs from the mia_material not quite right, you have to do it manually.

I think someone just posted an automated script for this on the mental images forum.

Rendering to EXR 16-half?

08 August 2011, 09:47 AM
Right now i'm rendering to EXR full 32 Bit.

Does it matter? Actually i wanted to have the full dynamic range.
And i thought to really get the best result, it would be best to render out
to 32Bit. Correct me if i'm wrong.

Thanks for your help David. Really appreciate it.

A sidenote.

One problem i have it the refraction. Maybe i can post an image.
But to get the glas and the stuff behind the glas to look right is really difficult, almost
impossible. I have to do some more tests, but it looks really strange.



08 August 2011, 10:14 AM
>One problem i have it the refraction
Realy hard to guess without image, the only thing coming to mind- do you have enogh refract rays in globals?
Ang generaly its dificult to speak about "looking wrong", cos it can be anything, and not realy wrong indeed. Fortunatley cant help you with comp in photoshop, newer use it for this.
Do you have ability to use Nuke(or fusion) for compose? The main goal, as i understand, to get same result after comp as you have in render view in maya, so with correct LWF it shouldn`t be an issure.

08 August 2011, 10:29 AM
Right now i'm rendering to EXR full 32 Bit.

Does it matter? Actually i wanted to have the full dynamic range.
And i thought to really get the best result, it would be best to render out
to 32Bit. Correct me if i'm wrong.

If you want a 32 bit output and then use photoshop to comp your images, you are wasting the half of your rendered images and you wasted time rendering the 32 bit images, as what I know, you can only tweak the exposure and brightness in photoshop for the 32 bit, the color correction in photoshop will only work in a 16bit exr as what I recall, so you will need to change your mode from 32bit to 16bit in photoshop to edit the color of your images.

08 August 2011, 01:34 PM
So does that mean, i should render my stuff to 16Bit?
Good to know that stuff about Photoshop.
I really hate it to work with it. But the images i create are all
stills and it is cumnbersome to post them in Nuke or Fusion.

So ,in other words, setting the Maya Framebuffer to 16Bit Half or Short?
And the passes to 16Bit or 16Bit unsigned? Get a little bit confused.


I know exactly what you mean buddy.
The main problem is that i can not recreate the look of my masterbeauty
with the passes. And especially the parts behind the glass are looking "wrong" or
in other words absolutely not the same way as in the masterbeauty.

I'm not sure, i have to ask before posting images but i'm under NDAs with that
product therefore it could be difficult.

08 August 2011, 06:19 AM
Would be best if you could reproduce it with something different and show it.

I might end up bringing the 16-half into Photoshop to get the correct exposure/colourspace and then colour grading in Lightroom.

Otherwise I'd use Nuke. But honestly, I like Lightroom for finishing. Less work for me (not much of a compositor) :-) And their grain removal works well if I use something like iRay or something else brute force.

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