I'm afraid I must annoy you with another weird issue.
I imported a video I shot on green screen, assigned it to the color channel of a material, then I also assigned the video's matte to the transparency channel.
Everything looked fine until I lit it, because the matted area are actually visible in reflections and they cast shadows.
I looked around, read a lotta thing, swapped materials, tweaked setting, I sent a preacher to the Lord I don't believe in, but I still can't get rid of this trouble.
Do you have any suggestion, please?
PS. There is -of course- a fairly simple workaround, which is the one I will make: compositing the images outside Maya. But I would still like to know how to fix this, in case it is usefull in the future.