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Alpha problems
Greetings, Cow. Here’s my problem: I’m building an open in Cinema 4D Broadcast r12, and using video with a premultiplied alpha from After Effects CS5. However, when I have the material set to use the alpha from the clip it get an odd darkening of the plane the image is on.
Example (with face removed for legal purposes):
As I’m new to R12, having upgraded from r8, I’m hoping this is an easy fix and I’m just missing something small.
Thank you in advance!
Brian Wheeler
Senior Editor
KXRM / KXTU -
5 Replies
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Have you tried a straight alpha?
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Thank you for responding! And yes. I’ve also tried inverting the straight alpha’s color and even putting pure white behind the talent. But that weird outline always seems to show up.
Brian Wheeler
Senior Editor
KXRM / KXTU -
is there environmental fog? (I can’t see it but I have to ask)
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AhHA! There was, and once it was removed the problem sorted itself out. A pity. I liked the look of the fog. Is there any way to keep it on and not get that effect?
Thank you all for your help!
Brian Wheeler
Senior Editor
KXRM / KXTU -
Unfortunately no. What you might do is generate a depth matte and use that to apply fog in post. Unfortunately that workaround requires yet another workaround as Cinema’s built-in depth pass doesn’t work with transparency.
You can generate a useable depth matte by giving all objects a material with pure white in the color channel, placing an omni light at the location of the camera, setting the omni to use linear falloff, set the falloff distance to the farthest object in your scene, and then check the light’s “Ambient Illumination” box (General tab). Then render out your custom depth pass.
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