Embedding 3D graphics in live TV?

Question

3D

Of course, I'm not sure that there are a lot of people working with live streaming, but still.
In general, the task arose to shove 3D graphics into a live broadcast, with which the filmed people will interact to some extent. Maybe someone knows how to implement it (software, hardware, methods)?
You need to get something like this: (several cameras will be used in the same way)
After watching, there were only two ideas left on how they implemented it:
1) Augmented Reality-marks on the floor + back wall and some kind of synchronization with cameras that do not see them
2 ) Just an overlay of a pre-rendered video. But here the question arises how they managed to make the character not drive on the floor when moving the camera.
PS As for the hardware for broadcasting, I only know that all the video from the cameras will go through and be broadcast through the NewTek TriCaster on which Windows XP is installed.

Answer 1

It is very difficult. If your camera will also move, then it must transmit a change in its coordinates along with the stream. In making such a video is not live, tracers are usually used, which restore the change in camera coordinates by changing specific points on the image. To do the same online you need super powerful computers. Therefore, it is better to transmit the camera coordinates separately.
In order for the hero of a real person to interact with 3D objects, and most importantly, to partially block them from the viewer, the person needs to be shot against a green (blue) background, and then the background (here it is the stage and the hall) is superimposed along with 3D objects.
Unfortunately, I can’t offer specific programs now, here you need to study what exists at the moment.

Answer 2

Read about the features of Blender.
Still, it is possible to solve your problem “impudently” (draw in OpenGL by overlaying video as a texture on a rectangle moved in space), but it’s easier to use ready-made solutions.