I am trying to output a simple emitter with an alpha channel to be used in Sony Vegas. When outputting the check alpha channel box does not permit me to check it. In Vegas I have tried most everything for the emitter to lay over top another video. Thanks for your help.
From the FAQ:
Can I save an AVI with an alpha channel?
No. particleIllusion (SE and 3.0 versions) does not support 32 bit AVIs. To create an alpha channel in your final output, render to a sequence of images, such as PNG, or TGA. All video editing software can load an image sequence and treat it just like an AVI.