View Full Version : Photographic Exposure + Ctrl Buffer

08 August 2008, 11:28 AM
Hey guys,

i know this is still a running thread, but recently i have heard
that you can use the photographic exposure Node ( or the exposure simple )
in combination with the ctrl Buffers.

So that all user Buffers are tonemapped with the both nodes mentioned above.

got anyone of you have experience with that? Or is it not possbile yet?

Your comments are greatly appreciated.


08 August 2008, 05:24 PM
AFAIK, the answer is no.

There is no way these tone map affect user frame buffer, they only work on main frame buffer.

Maybe we will wait for new release of Maya for these feature work, or another good guy could make a custom tonemap shader to help all of us

Too bad a simple thing like this is not in MR. (as usual)

08 August 2008, 06:13 PM
hey mate,

yeah its really a pity - i just dont get it why its not implemented - like
many other things - seems to me to be a running gag...

Have you tried the tonemap options which come with the Buffer Api?
Would be interesting to hear your opinion.

Nevertheless - we have to wait for the next version...



08 August 2008, 01:47 PM
Have been fiddling around with this and many other things while trying to learn ctrl buffer. My conclusion is as ghostlake is right as far as tonemapping buffers is concerned. As for the buffer api, it's built in tonemapping works great in viewport (all in one) render, even works great to preview different passes by placing the buffer pass into primary buffer. would probably be doable even to switch passes around one by one to primary buffer to batch each pass with proper aa and tonemapping etc.

However since (as far as i know) the api node itself cant batch render the full final pass product, you have to use buffer write that does not make use of the primary buffer the same way api node can, thus the result is all other then pleasing. For example the need for higher aa (1:2 or even 2:2). In the end i might be doing something wrong but from my pow it is simply to much hassle trying to set up what is already working in the primary buffer where you also have the option to use the built in tonemap nodes etc.

One idea i had, not sure if and how to do it though (please do let me know if you know how to do it) would be to use ctrl_buffer and or mix8layer as "extractor" for different shaders and output the resulting passes into the native render layers in maya. This wouldn’t give the benefits of render buffers but it would at least solve many of the existing issues with integration to mental rays framebuffers. Any idea how and if that would even work?

Many hours later and im still not sure what to make of this. I have tried different things but not getting it to work. If i hook up a buffer api in my scene, i can effectivly make a bunch of regular render layers and via animated render overrides replace the primary buffer with whatever is currently checked in the buffer api (spec, reflect, dif etc). However whenever i batch render all i get is the first layer over and over since the api node does not update or write other then in the renderview. So the question is if there is any manual way to hook up the current result to the render layer pass?

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08 August 2008, 01:47 PM
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