In the few tests I personally did, I didn't need the edge blending in such situations. In the projector have different angles, they will not give the same light energy depending on the angle between the video projector rays and the object surface (a surface that is perpendicular to the projector will be brighter than one where the incidence is 45 degrees)
If you need to edge blend to adjust, you'll have to:
- Map the OBJ file once per projector
- Manually put quads on top of it to handle fade out where needed, using mesh warping or quad masks to adjust the orientation.
I did a quick demo here:
https://www.youtube.com/watch?v=7VstsEfE-yc