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Removing a VraySun's Direct Illumination


braddewald
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The Situation: I have a simple scene set up--a square room with a window, illuminated by a VraySun and VraySky. Everything looks just the way I want it to.

 

The Problem: The sunlight is coming through the window and creating a huge square patch of sunlight on the floor. I want to remove that square patch of light without changing the illumination that it is providing. Is it possible? (If there is a way to do it in photoshop using some blending mode and a vrayrenderelement, that would work too).

 

I want to be able to switch back and forth between one image with and one without that patch of light without seeing any other changes to any of the other pixels in the image.

 

I know it's kind of an odd problem to have, but I'd really appreciate some help. Thanks in advance.

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I am sure there are other ways, but it would work if the sun were shooting through a glass.

 

If so, you could calculate the GI passes and save them for use in the final render. Then in the glass material rollout untick effect shadows. This will keep the suns rays from passing in, but still give you the same GI pollution that you had when the suns rays were passing in.

 

This will work because direct light rays are not baked into the light solution, then light solution is more or less the GI light which is effected by the direct rays after they reflect off of their first surface. Or something like that.

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This is how I did it...

Create Daylight System/Change to VraySun and accept VraySky in environment. Turn OFF the VraySun.

Create VrayLight at window, no portal just plane at window.

Create a new VraySun at the same location of the first and change intensity multiplier to .1

 

The VrayLight at the window ended at a multiplier of 65. How was this number obtained? By doing a False Color render on the original Sun and Sky; then turning Sun off and adjusting lVrayLight until the same average illumination was obtained. The final Sun low value actually caters to the excellent range of the average human Eye balls....

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What ever became of this issue? I did not get these conditions met with Travis's suggestion, "I want to be able to switch back and forth between one image with and one without that patch of light without seeing any other changes to any of the other pixels in the image."

 

Bradley?

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Travis,

I did not get your results. I am sure that I am going to try again what you said but in the mean time could you please post two images.

 

Tried every way to render "From File" but I could never get The results Travis gets with what I get. There is a huge difference in pixels in one set. So yeah, post some images please.

Edited by Ismael
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Travis,

Thank you for the demo. I finally figured out my puzzlement! The VrayLight which I had placed on the window, for me to get the same results as you, I needed to calculate the lighting with a check on "store with irradiance map". It appears that the direct Sun contributions are otherwise and by default always stored with irradiance.

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