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threehundredbpmshredder
04-03-2007, 02:37 PM
Hello there. I am trying to render the shadow of a sphere over a plane. I want the shadow to be visible and nothing else. In other words, I want the whole background to be transparent except for the shadow.

I tried unchecking the sphere's primary visibilty and it did good. The sphere became invisible although the shadow was still lying on the plane. I used point light (light color=black, shadow color=green). The problem is the plane. I couldn't make it transparent like the object. When I uncheck the primary visibility of the plane and render, the shadow disappears. I tried using "Use Background" shader and it did the same thing (the shadow didn't appear).

Am I doing something wrong? Is it impossible to render a shadow with everything else transparent? Thanks in advance.

eodmpink
04-03-2007, 03:37 PM
You need to make sure to turn off reflectivity under the background shader attributes. You should be able to see the shadow in the render alpha.

swellhead
04-03-2007, 04:00 PM
Set to zero the plane shader's matte opacity. This will render a green shadow, the problem is there is no alpha for the shadow. If you are going to comp this, you should set the alpha mode to something like luminance. HTH.

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04-03-2007, 04:00 PM
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