MR - Sun and Sky - Wash out & Flat

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Old 03 March 2013   #1
Red face MR - Sun and Sky - Wash out & Flat

I'm outta practice when it comes to doing Maya projects. Been a little while since I did a mental ray "sun and sky" indirectly lit scene.

I've just wasted over an hour trying to figure out why my render is so washed out and flat. Especially the red portion of this logo:


I'm losing hair trying to figure this out. I'm sure it's the usual some check box it not selected or shouldn't be selected.

I'm using a Phong on the red. It's like it is glowing. I've tried lowering the sun intensity. I've tried raising it. Doesn't seem to effect the render at all.

Any help would be appreciated.
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Old 03 March 2013   #2
What's your Gamma setting?

And do you have any other lights in the scene? Are you using a mia photographic exposure camera shader?

More of your set up might be helpful.
 
Old 03 March 2013   #3
I vaguely recall there possibly being an issue if something something was connected with a multiplier node prior to any gamma adjustment (the issue would be with the adjustment values), with a rendering becoming desaturated. I heh might be wrong here ofc.
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Old 03 March 2013   #4
When you apply sun & sky in MR, it adds a gamma correction to your camera. Make sure you set that back to gamma of 1 if you're already color correcting your render view
 
Old 03 March 2013   #5
Thanks everyone for jumping on this issue.
I found the gamma adjustment setting was defaulting to 2.2. So I tried setting it to 1.0 Here's how the render looks after:


You can see that while it certainly created a greater range of dark to light the Phong is still glowing like it's radioactive.

Here's a screen shot of my Sun & Sky default settings:


Again, any help is greatly appreciated and comes with a mai tai offer if you're ever in the islands. Mahalo.
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Gary Turner
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Time Warner Entertainment
Honolulu, HI 96813
 
Old 03 March 2013   #6
Google "Linear Workflow"
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Old 03 March 2013   #7
Question

So are you saying that "Linear Workflow" explains why the red phong is incandescent?
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Gary Turner
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Time Warner Entertainment
Honolulu, HI 96813
 
Old 03 March 2013   #8
It is because there are many points in the pipeline where the gamma comes into play. I agree. look into Maya linear workflow to see if you can track down where it is going wrong.

Also another tip is to look into your sun and sky saturation, red/blue shift and haze settings. By default it is very blue. That can be controlled by these parameters.

Last edited by cineartist : 03 March 2013 at 09:18 PM.
 
Old 03 March 2013   #9
Do you have any selfillumination on your Phong? To start off, I would use MIA_X materials instead.
 
Old 03 March 2013   #10
Simply put,

to me its gamma issue in shader...

As others said, you need to correctly set up linear workflow esp when using hdr like PhysicalSun system...

Its too long topic to write it again and again so check other "LinearWorkflow" threads...theres is a recent one in which Ive described it.
 
Old 03 March 2013   #11
Well I sat through the four video tutorials at Vimeo. They were quite informative. So I have a better handle on linear workflow now.

BUT, I continued to have incandescent issues with the red phong shader. I was able to tweak other shaders combined with color correction in AE came up with something passable. Wish it could have been better though.

The Fiat logo was actually purchased through Turbosquid. I initially had some issues with not being able to get a non-faceted smooth render with the model. Couldn't figure out why I was getting such hard edges. I notified the creator of the logo and he made adjustments to the model that fixed that issue. I have a feeling that there's some other odd setting with the purchased model that was creating the radioactive glow.

In the end we found a work-a-round.
Thanks for everyone's help.

I now have a better understanding of 32-bit images. That can't hurt knowing!
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Gary Turner
Producer/Director/Animator
Time Warner Entertainment
Honolulu, HI 96813
 
Old 03 March 2013   #12
You can go to Utilities in the hypershade and change the exposure node from 2.2 to 1
 
Old 03 March 2013   #13
i actually liked the original image.. all soft and fluffy.. I was waiting for a kitten to pop out!~
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Old 03 March 2013   #14
Models from Turbosquid often have some amount of 'ambience' set on the phong material. Usually dark grey. The various linear workflows will make this ambience more pronounced. If that's what's happening turn it back to black.
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Old 03 March 2013   #15
If you're rendering in mental ray, you should not be using a Phong or Blinn or other native shader. You can still keep the Phong, sure, in your Shading Group. But override it in the mental ray section and replace it with a mia_material_x.

It will render faster and be energy-conserving as well, and more physically accurate.
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