Movies can't be transparent, as far as I know...

Is your intention to add a background later in postwork for the video? If that's so, you should render simulating a chroma key (bright green or bright magenta backgrounds in Poser, or any other color that's very different from any color rendered in your figures or whatever you're rendering). Then, in your video editing application, pick that background color as a chroma key and use the rendered movie above a layer with your background picture/movie (Adobe After Effects and Adobe Premiere do that marvellously).

 

Without that, I doubt any video editing program will import transparency data, unless you have Poser's Make Movie feature save as image sequence instead of a video file (but then you'd have to import the images one by one in your video editing app, or use some plugin that does that for you).

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Feel free to call me Ohki!

Poser Pro 11, Poser 12 and Poser 13, Windows 10, Superfly junkie. My units are milimeters.

Persephone (the computer): AMD Ryzen 9 5900x, RTX 3070 GPU, 96gb ram.