The ability to add a transparent background to a Vyond video is not currently available. However, there is a work around:
1) Change the background color to green:
2) Add any assets or characters needed in the scene:
3) Export your video as an MP4 file:
4) Use an outside program to key out the background to isolate the character
This webinar led by our video producer, Taylor Morgan, goes into further detail on how to do this.