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Gilles Tran wrote:
>
> in MP radiosity, a good balance of
> light intensity vs brigthness can give amazingly "good" (meaning visually
> satisfying) results.
There is a way to balance radiosity and light sources after the render
in a photo editor. Since radiosity takes much of the total render time
lets just render it once and tweak it afterwards interactively :) This
is purely for artists to get desired results and ignores the scientific
stuff except gamma :) Yes, can't get rid of that since we are after all
dealing with CRT displays.
We need:
1. Image editor that has additive layer mode and a method of editing
gamma 1.0 images so that the gamma correction is applied only to
the displayed image.
2. One render of the scene without assumed_gamma statement with all
the lights and radiosity on.
3. A render like 2) but without radiosity.
4. Subtract image 3) from image 2). This leaves just the radiosity.
The interactive part:
5. Load image 3) to layer NORAD
6. Load image 2) into a separate layer RAD with additive layer mode.
7. Set the image editor to perform Display_Gamma correction on the fly.
8. Now you can adjust the RAD & NORAD layer transparency, histogram,
transfer curve, brightness, contrast etc. Try to get what you want
first with the transparency and histogram operations and then try
the others.
9. Flatten the image, apply Display_Gamma correction to the image
data and save.
I tried this with Photoshop to tweak media & lights but it has a
couple of limitations.
- No additive mode. Screen used instead (it works because there are only
few overlapping bright areas in the image).
- Gamma correction done with curves adjustment layer so it's fixed.
- Not possible to edit 48bit images.
Have a look: http://hammer.prohosting.com/~kkivisal/splash_layer.zip
Hollywood Gimp is supposed to be able to do this properly when it's ready.
______________________________________________________________________
Kari Kivisalo http://www.kivisalo.net
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