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Light Transmission Not Working in Active Camera

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Matthew Pizzano
Light Transmission Not Working in Active Camera
on Feb 24, 2012 at 8:40:13 pm

I recently read Meyer's tutorial on using light transmission to create the look of a video projector in 3D -

The idea is that if you create a 3d world... you can point a light at a foreground layer, turn on create shadows, turn light transmission up to 100% on that layer so the light transmits through the foreground object and "projects" onto the background layer.

I've tried to push it a little bit further by putting two layers in the background.

The furthest in the background is the screen. Its been turned on to 3D and can accept shadows. The middle layer is a rotoed out person. He too can accept shadows and is in 3D.

The foreground layer is a piece of video footage I would like to project onto the background with the person causing some occlusion between himself and the screen behind him.

**Please check out this picture for a screen shot of my camera views:

HERES THE PROBLEM. The effect works wonderfully in every single camera angel EXCEPT the active camera. Whats bizarre is that the light transmission works from the mid ground guy to the screen, but the active camera is completely ignoring the piece of video footage.

I initially thought that AE couldn't handle 3 layers for light transmission, but strangely, even if I turn off the screen in the background the effect won't work from the blue video onto the guy.

Does anyone have any thoughts??? The point of interest doesn't seem to make a difference as it looks the same regardless if the point of interest is on the videos plane or the mans.

Most dummy checks have been gone through - the video layer is in 3D. It should work since the other camera views see it...

Please help... need this for an upcoming delivery... Thank you so much!

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Roland R. Kahlenberg
Re: Light Transmission Not Working in Active Camera
on Feb 25, 2012 at 2:59:24 am

Cases like this, where things look fine only in the non-active camera view, usually involves a 2D layer disaffecting 3D layer interactions. Check your timeline to ensure that no 2D layer is stacked between the 3D layers.

If this still doesn't solve your problem, then provide a snapshot of your timeline


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Darby Edelen
Re: Light Transmission Not Working in Active Camera
on Feb 25, 2012 at 6:39:17 am

So where is the screen that your image projecting onto? I only see the projection image, which appears to be in front of the background images (obscuring them from the active camera). Generally you'll not only want your projection image to be set to 100% light transmission, but also to Cast Shadows - Only.

The plane that your projector is casting onto should be 3D, white (or close to white, it could be an actual image of a projector screen), and set to Accept Shadows - On and Receive Lights - Off.

Darby Edelen

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Darby Edelen
Re: Light Transmission Not Working in Active Camera
on Feb 25, 2012 at 8:32:31 pm

Here are some pictures to show a setup that works pretty well.

Layer Breakdown

Shadow Map Settings

Darby Edelen

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