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Tone Mapping for Lighting (Read 3561 times)
chrismmurray
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Tone Mapping for Lighting
11/13/07 at 17:18:31
 
Hey all,

Do you need to (or even want to) tone map an HDR that you will use for lighting?

I've read the tone mapping chapter Smiley but unless I missed it, I can't find any mention of that...

Comments?

Chris
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Blochi
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Re: Tone Mapping for Lighting
Reply #1 - 11/13/07 at 19:09:02
 
Keep reading Smiley

Chapter 7.3 will answer your question.

Bottom line is: Not in the same way tonemapping for photography is done, but it doesn't hurt to adapt some of the methods. Just with a different goal in mind.

Blochi
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chrismmurray
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Re: Tone Mapping for Lighting
Reply #2 - 11/13/07 at 19:27:29
 
Ahh yes. Good ole 7.3. That is a heady chapter indeed! That is a very meaty section of the book.

That is essentially where my struggle is at the moment.

3dsMax and gamma has always been an enigma. I guess I've been using the cheater's work flow because I ignore gamma in max and just make it look right in the composite.

I find that introducing gamma either dorks up the texture maps or the background. So I'm at the point now where I just planning on not having the background be part of the rendered image. (because max's gamma adds to the gamma of the image and then the cg element is out of synch with the gamma of the bg.)

I'm trying to build a work flow that gets you a reasonable result directly out of max, but I don't think thats gonna happen. Some of my clients are arch visualization and compositng is totally foreign to them.

So I assumed the correct answer to my question-- you just confirmed it.

Thanks,

Chris
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Blochi
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Re: Tone Mapping for Lighting
Reply #3 - 11/14/07 at 19:54:53
 
True.

Well, at least in Lightwave I found it to be easier when the visible background is separated from the lighting HDRI. Fits several purposes:
- you can have extreme resolution on the Background, that would screw up lighting.
- you can take your time and properly tonemap the background beforehand. Instead of just a simple Gamma, you can use all Tools from the tonemapping chapter...
- and your background image will be more memory efficient when it's an LDR image (PNG or JPEG) already.

This was another thought behind automating advanced rigs like this with the Smart IBL system. The Lightwave sIBL version does indeed set the proper Gamma values for the Cheaters Workflow automatically... Although the dev team had some great discussions about implementing a Linear Workflow here as well.

Blochi
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Gerardo
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Re: Tone Mapping for Lighting
Reply #4 - 11/17/07 at 03:33:46
 
Perhaps they could add both options.



Gerardo
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