Projection mapping on 3D objects is achieved by creating flat media that “wraps” around the object, using coordinates defined in a 3D model’s UV map. The UV map is like a flattened version of the 3D model, unwrapped and laid out flat. Media that has been created aligned to the UV map displays accurately to the coordinates of the 3D model.
The 3D model or “mesh” is used by the media server in a “scene” where projectors are defined relative to the position of the mesh. By calibrating the projectors’ location, rotation, and lens characteristics, the media server can calculate which surfaces of the mesh correspond with the pixels from each projector.
If a motion capture system is used to track the movement of the physical object, that position and rotation data can be attached to the mesh in the scene, and the calculations of what surfaces correspond with each pixel of each projector update.
The UV map defines what pixels from the media are to be drawn at what coordinates on the surfaces of the mesh. The calibration of the projectors and the mesh within the space defines what pixels in the projector to light up based on which of the mesh’s surfaces are facing the projector and in what orientation.
Moving the physical object updates the tracking information connected to the mesh in the scene, and everything recalculates.