Using real camera and projector with correct parameters.

I am a complete unity noob working on an existing unity project as part of something else.
I have a scene on a tabletop with overhead camera and projector - I have calibrated the camera-projector stereo system, and I need to take camera 3D coordinate location of a laser dot on the tabletop and convert it into image location on the projector.
What confuses me is this -
How do I represent real world coordinates from the real camera in the unity world coordinates, and using these, set-up another virtual camera at desired (R,T) from first camera?
How do I attach camera matrices and distortion parameters that I have to these cameras? (It seems unity expects cameras to be orthographic but the standard camera model is perspective matrix)

  1. Unity units is meant to be meters, but that depends of your modelling and models import settings.
  2. Unity Cameras can be orthographic, it’s the default if you chose to begin a 2D project, but
  3. they are perspective based otherwise, and
  4. if you use the latest version of Unity (2018.2), you get real world cameras presets.
  5. Although, this solves the FOV for you, but doesn’t add lens distortion, this requires post-effects.

Hopes this helps.