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chibley

Matching shadow color to photo backplate using shadowmatte / AOVs?

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Hi there,

 

I am trying to integrate a simple box into a photograph that I found on the web. The idea was to just experiment with matching lighting and shadows. In my scene, I have created a grid for the ground, and roughly lined it up with the objects in the photopgraph. I then placed a box on top of the grid and used a distant light, and an environment light to light the scene.

 

I applied a shadowmatte to the ground plane to catch any shadows occurring on it which has given me a nice alpha channel in which to composite shadows.

 

post-12039-0-42150800-1418465964_thumb.j

 

post-12039-0-82647100-1418466827.jpg

 

My problem is that in the scene, the dog is casting shadows with a slight blue tint to it. I would like to match my box shadow color to the dog's shadow color. I understand that I can apply a color to the environment light to match the color temperature of the photograph, thus matching the shadow colors too, but obviously this won't work with the shadowmatte as it contains no color information.

Obviously if I were casting shadows on a mantrasurface or similar diffuse surface I would get the proper colors of the shadows, however I would like to achieve this effect using the photographic backplate.

 

post-12039-0-74768800-1418465960_thumb.j

 

post-12039-0-55144300-1418466825.jpg

 

Is there any way of achieving this with shadowmatte or AOVs, inside Houdini? Or does this need to be faked in compositing? What would be the best approach to this simple object integration?

 

Any help would be really appreciated!

 

W.

shadow_test_04.hipnc

Edited by chibley

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I put together a short video on how to tint shadows in the COP network.

 

You can check it out here:

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I put together a short video on how to tint shadows in the COP network.

 

You can check it out here:

Wow, perfect!

 

Thanks a lot, Atom! Would this be the only realistic way to match shadow colour for a photo backplate?

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I doubt that this is the only way. I am just learning Houdini myself.

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Guest tar

 What would be the best approach to this simple object integration?

 

 

The best approach for this one is simply to do it in composiitng

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