I know there have been many threads on Alpha Channel, but I have not seen one that can explain my problem. I create an object in a 3d software and animate it in a sequence of images and imort it as a background in PI. I refer to the tutorial on how to get emmitters to go around 3d objects and I follow the steps to the tee and it works. The problem comes in is when I am recording or exporting these frames as sequence of images and import them into my video editing software (Vegas Video), all I see is the emitter only with no background, but I do not see my object once I do straigt matted or or dirty. I tried every export scenario, whether turning on BG or different export files(i.e. TGA, TIFF,PNG).The only way it works halfway-decent is if I place a color background behind it and color key it, but the output quality is horrible. Is there a tutorial out there that takes you from start to finish on something like this? Can someone help me with this one!!
It would help a lot if you were able to post up a copy of the scene for us to have a look at. If you could include just one frame of the background sequence rather than the whole thing so maybe someone here can figure it out.
The only reason I can think of for you having any problems with this is that pI doesn't output the alpha channel of the background image when you render something out. It will render the the colour of the background image into the final image, but only the alpha channel of the particles.