Author Topic: Question - Is possible to render lighting channel without color channel? Ondra?  (Read 2663 times)

2015-03-31, 00:38:36

juang3d

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Hi there.

I have this question, I'll esplain why, I have a job where I will have to render A LOT of images that will be exactly the same, except that I will have to change some logos and some colors, those colors won't affect too much to the illumination (well, the may affect but it's not important if I change them and it's not perfect) so to avoid having to render 50 images with 50 different textures I wanted to render the elements without the "color" element and having the color in a spearate element, this way I could be able to replace the texture of the object with the logo in comp using the UV channel and skip those additional renders that could take A LOT.

Check the attached picture, I think it's a better explanation, you can see th teapot with face as the rendered one, and you can see how I changed the teapot texture with a bricks texture in compositing, I did not have to re-render anything, just change the texture in comp.

So it's possible to do this right now?

Cheers.

P.S.: ignore the gamma shift in the result and the different elements, it's just because I made this explanation picture fast and that was not an important thing.

« Last Edit: 2015-03-31, 00:59:49 by juang3d »

2015-03-31, 00:50:29
Reply #1

juang3d

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I achieved to gat the color pass, but I can't find a way of getting the different lighting passes to arrange the final render.

Cheers.

2015-03-31, 03:03:16
Reply #2

Njen

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Because the albedo value of an object bounces light back in to the scene, falling on objects around it, it maybe impossible to set up something you are requesting.

If you have a red ball on a grey surface, the reflected rays off of the red ball will bounce red on the grey surface. But if the ball was blue, then it will bounce blue. So even if you are able to have multiple albedo renders and a hue-less render to multiply it against, you will lose the colour bleed information that comes from having the proper albedo values on the objects in the first place..

2015-03-31, 10:00:42
Reply #3

juang3d

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I know that, the result won't be physically correct but this is possible in other engines ( in the image is the example).

I'm not looking for correctness here, I'm looking for usefulness :) i don't care if the reflected color in the floor is red because the original texture was red, but I need to change the texture, so I need the lighting in a separate pass,even if it is the full lighting not direct and indirect, I don't care if there is no such separation.

Cheers.

2015-03-31, 15:46:37
Reply #4

Ondra

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yes, this should be easy to do by combining RawComponent and SOurceColor render elements
Rendering is magic.
Private scene uploader | How to get minidumps for crashed/frozen 3ds Max | Sorry for short replies, brief responses = more time to develop Corona ;)

2015-03-31, 16:05:27
Reply #5

juang3d

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This is what I though, but the raw componente is giving me the texture also, check the attached pictures.

One is the raw component, I'm getting part of the texture in the component, can it be because the strokes are plain black? It's weird.

Cheers.

2015-03-31, 16:51:19
Reply #6

Ondra

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yes, you cannot reconstruct raw lighting for 100% black - that would result in division by zero
Rendering is magic.
Private scene uploader | How to get minidumps for crashed/frozen 3ds Max | Sorry for short replies, brief responses = more time to develop Corona ;)

2015-03-31, 16:53:14
Reply #7

juang3d

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Another curious thing, when I use the source color, it doesn't give me a complete plain color, but it has some kind of shading, check the attached pictures, as long as I wasn't using any reflection it was plain color, but as soon as I added some reflection it gave me that kind of "shading" in the color element.

2015-03-31, 16:54:14
Reply #8

juang3d

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I was posting at the same time you answered.

Ok so the black color is the problem, that's great because it's under control :)

What about the "shading" in the color element when I put some reflection in the object material?

Cheers!

2015-03-31, 17:29:15
Reply #9

Ondra

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that is just fresnel. If you add reflect + diffuse source, you will get your "unshaded" render
Rendering is magic.
Private scene uploader | How to get minidumps for crashed/frozen 3ds Max | Sorry for short replies, brief responses = more time to develop Corona ;)

2015-03-31, 18:02:34
Reply #10

juang3d

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Ok, perfect! :D

Thanks Ondra, great to have this workflow in Corona... AWESOOOOOME!!!

Cheers