I'm new to after effects I've only been using it a few months and honestly I've not been loving it, but that's neither here nor there. I have tried to use the rotobrush many times but most of the time it just wasnt worth the effort but this time I had a short clip with not a lot of movement and pretty good contrast to the background so I thought OK, lets do it. It still took a little work but I wound up with what I thought was a pretty good effect. Then the problems started when I tried to render. I first wanted to render a transparent avi or mov file. Looked up tutorials, thought I did what I was supposed to, wasnt working though, so I said fine imported the full video that had the clip I wanted into the background and AA crashed of course, My PC is medium beefy but only 16gigs of ram, and AA goes through ram like crazy. Luckily I saved because AA has never once been able to restore a unsaved project for me. So I rendered the exact clip elsewhere imported that put it underneath the rotoscoped file looked fine in the preview, I was gonna just back it on that way and render and an MP4 but every time I rendered the rotoscrope video was invisible. I tried rendering through the media encoder and after effects. Can someone possibly tell me what T I need to cross to get this to behave the way I want, if you need a screen shot of settings or anything just tell me what you'd like to see. I suck with AA but I have experience with other programs in the video editing, post production space. This is my first and perhaps last dance with adobe software after my year is up.