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View Full Version : Tonemapping channels (in FXTree)


Gabba
01-02-2009, 11:09 AM
Hi guys! I posted on the xsi community forum asking if there is a way to tonemap the render channels because it seems that lens shaders doesen't work on channels. The answer, like I said before, was no, because the framebuffer (except for the beauty one) are not processed by the lens shader.
So my question is, how can I tonemap the render channels in post via FXTree? What is the "correct" way??
Output all the channels in .exr format, correct them in photoshop and then put them togheter in FXTree or there is a way to get "all in one" in XSI?
Cheers

Gabba

theotheo
01-02-2009, 11:24 AM
I don't use xsi or know the fxtree that much. But can you enter per.pixel expression operations in it? That way it would be easy to create one yourself.

You can use a simple tone mapper to get some decent results (but it will probably deviate from the algorithm the built in lens shader uses)

L = Y / (Y + 1)

or for each channel it would look more like

RED=RED/(RED+1)
GREEN=GREEN/(GREEN+1)
etc etc.....

And you could substitute the 1 with a arbitrary number to modify the results.
http://en.wikipedia.org/wiki/Tone_mapping

If you got access to fusion I could give you a couple tonemapping plugins ive written.

Hope this helps :)

-theo

Gabba
01-02-2009, 12:09 PM
@theotheo:

Thank you I will give it a try! =)

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