Mia_X Output Passes and ToneMapper - Simple Exposure

[asche]

i get what you mean :)
i spent some time figureing it out but i didnt come to a conclusion
managed to get the same result in post with untonemapped passes, but as soon as you use compression in the tonemapper it looks different , i couldnt figure out the way the tonemapper compresses the values

if anyone knows how, tell us :)

best would be a description how the photographic tonemapper works :)

[naik]

but as soon as you use compression in the tonemapper it looks different , i couldnt figure out the way the tonemapper compresses the values

if anyone knows how, tell us

yeah thats the problem - i cant get the simple Exposure results in post also.
It would be very neat if one can apply the tonemapper to the output Passes also...

Perhaps anyone got a hint..

cheers

NAIK

[Gal]

what workflow do you use for your passes? please elaborate on your steps in detail

[naik]

Hey Gal,

nothing special.

I use the Mia_X Shader in Combination with the SimplePasses in order to get out the
different outputs of the Mia_X.

The Camera got the simple Exposure Node connected to it.
But it seems that the output Passes will be written to disk before they reach the
exposure simple Node.

You got a workaround?
I can not recognize how to connect my exposure simple node to the "mentalrayOutputPasses" / "UserFramebuffer"...


cheers

NAIK

[Gal]

not sure what i can do but let me look around. by the way i tried to d/l simplepass shader from www.wiki.render3d.de to try and find a solution but the link to the shader doesnt seem to work. know where i could grab it?

[ghostlake114]

I got what you mean, first, at the momment, except u have an inhouse programmer to make a special buffer write shader, u must accept the rule of current pass shader like ctr_buffer or simple pass

So after get pass, which not to be tone, you will need to re-tone them in post effect, so you need to grasp the theory of mia_simple

http://toi.bk.tudelft.nl/toi-pedia/index.php?title=Rendering_Mental_Ray:_Tone_mapping

Currently, what I do is change the gain and gamma of rendering pass, that bring much effect like mia_simple bring

pedestal,most case we dont touch them
knee and compression: I really dont care much about their effect :beer:, I never try to stimulate this effect, but they could be done by a operator in compositing

[naik]

Hey Gal,

i have sent you an email with the shader.
Perhaps you can find a solution.

ghostlake114,

i have tried to achieve the same result in post with the untonemapped passes.
I will certainly try it again but for now i couldnt get the same results
although it must be possible to achieve that.

"knee and compression" i think especially these two parameters are important
for my purpose in order to crush down the whites...

I will try it again in combustion - perhaps there is a way...

cheers guys

NAIK

[ctrl.studio]

but you cannot compose gammed and tonemapped passes together.
the way the tonemap works only on the primary buffer is correct.


a crazy thing you can do is to use ctrl.buffer and ctrl.multipass.
you do save a 'pass' with all the buffers in it. then you switch your main buffer with sec buffers (ctrl.buffer allow you to do that) for every buffer you have to tonemap. technically you use mr as a compositor apz. but probably this will confuse you even more. :)

max

[naik]

hey max thanks for dropping in.
I understand what you mean.

But my problem is that i work with Maya 2008 Sp1 and i thought
the shaders you talked about are not compatible with that version.
(Because of the new "broken" Framebuffer API..)

Tell me if im wrong...


cheers

NAIK

[naik]

So Max, does your shaders are running on Maya 2008 Sp1 64 Bit?

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