You would need to track the person and link that position data to the Billboard (projection) plane. I know it’s been done,  but it would be nice if Aximmetry could implement this as a standard, documented feature. Even better would be a basic OpenCV full body bounding box tracking to do the shadow tracking automatically without external track. It would basically move the plane in Z space according to the where in the video frame the lowest pixel cluster (the feet) on the keyed alpha was positioned. 

Merry Christmas, thank you. I also asked the official, but they have not responded yet. This technology should not be difficult to implement, but it should not be available in Aximmetry. Shadow tracking is too important. It determines the relationship between the early stage of creation. I hope that the official can solve it in the future. Otherwise, it will be more convenient to use ue4.

I’m not sure I understand what you mean with “but it should not be available in Aximmetry”? And why would it be more convenient to use UE4, which doesn’t have this feature at all?

UE4 can get the location of the htc tracker to track billboards, can Aximmetry do the same? But I don't know how to bind billboards in Aximmetry.

Yes, of course it can be done in Aximmetry, as I said in my first reply. You’ll just have to set it up yourself )just like you would in UE4), since Aximmetry hasn’t implemented a standard compound to do this. I’m not sure, but I think you’ll have to add a Game Pose module and connect it to the Billboard coordinates. There will probably be some math involved to offset the transform correctly and possibly limit what axis you apply the transform to.

Thanks!!!