Hello!
I’ve been trying to figure this out for a while now, and I cant find anyone who knows how to do this. I’ve made a flash movie of a guy walking, with a completely transparent background for the flash movie. I added in a plane in blender, added a new material and texture. I set the texture type to “image or movie” and chose the flash movie(.MOV)that I made. In the influence settings, I checked alpha and turned it all the way up. I checked premultiply as well, then I went into materials settings and turned transparency(Z Transparency)on, and turned alpha all the way down. But the background of my .mov is still there, and thats what I want to get rid of. It works with after effects, the background is gone be default, but I cant get it to do the same with blender. I put in a sample image of my problem in this forum. Help? 
Thank you!!
-Oliver
