2 cameras, 2 screens and overlap issues in real world

Questions & Answers
1

I have a working projection mapping setup that I’m now adding more effects and objects to. I have two real world projectors that are aligned to the into scene cameras. After getting everything calibrated and working in both environments I’ve started to add more to the scene. This is where it breaks down for me.

I have two projection mapping Epson projectors. They have an ability to fade pixels in overlapped areas so that it produces a single image. The ultimate resolution is 3180x1900. The real world has a logo mounted to the wall that is mapped so that the game objects textures are projected into it. There is a plane that plays videos from a network source and that is all good.

As long as the objects in scene are at the same distance as the currently calibrated objects in the scene, everything overlaps and matches in the real world scenario. If I move the plane for video back or forward from the current position, the overlap no longer works. Everything is in perspective because that’s how reality works.

Is there any way to make it so the objects always overlap correctly at any distance from the sets of cameras? I thought about using one camera and then the two cameras view the output of the one camera. However, I think the trade-off with something set up like that would be that the central camera doesn’t show the correct perspective of the other two. Any suggestions on this would be helpful. I may be overthinking it all.

2

If I understand this correctly, you have two cameras which both face the same direction rather than having converging aim/rotation, right?

Following that train of thought, you can calculate your Frustum Size at a Given Distance, then use those values as your separation between the two cameras in Unity.

With this in mind, you can scale the result slightly by the overlap of the physical projectors relative to their baseline Frustum Width, and the result should be pretty consistent.

3

bdubbert gave me the best answer but, not as an answer so I cannot vote it up.

To get my overlapping screens to render everything correctly, I had to move the cameras to the same position. I then offset the view instead of moving the cameras to the location of the real life projectors. I overlapped them the same way I had in the original setup. The only difference being that the real world light hits objects at different angles than what the current perspective allows for.
To combat this, I have to rotate the in game objects to produce the same light output to the mapped items in the real world.