There are several forms and corresponding solutions of projection mapping with TouchDesigner.
Kantan Mapper is a projection mapping and masking tool where you define 2D polygons and bezier outlines in the field of view of a projector, then fills each shape with a selected image (TOP).
CamSchnappr - If you have a physical 3D structure plus a virtual 3D model of that structure, you can to project a rendered virtual model onto that physical structure perfectly-aligned, by choosing and moving 6 guid epoints in your projected image. It can do multiple projectors with blend regions.
Stoner - An interactive corner-pin image warper plus a mesh warper for manually fitting an image on a physical 3D surface.
Vioso is integrated with TOuchDesigner and lets you read in calibration data from the VIOSO Calibrator Software. Vioso's auto-alignment technology makes the setup of installations like multi-projector panorama displays and multi-projector setups for projection mapping more automated and quick.
Scalable Displays - The Scalable Display TOP lets you load calibration data retrieved from running the Scalable Display Calibration Software.
See also Corner Pin TOP - brute-force corner-pinning.