Projection Mapping 101

There are two main ways of working with projection mapping:


METHOD ONE

One is based on creating a virtual 3-D model of the objects/forms you want to project onto.
The idea is then to match exactly the position of the projector with that of the virtual camera in the 3-D model, so that the virtual model maps exactly onto the physical form. This is extremely meticulous work which needs exact measurements and many rounds of calibration, but can produce some great results.

Example of application. A real amplifier is place to acertain angle. The from the angle a 3D model is created. The 3D model then guide the application of graphic onto the model according to the perspective of virtual camera. The perspective of the virtual camera is then substitute with a projector.

METHOD TWO

The other way, which is what VPT( video projection tools) is based on, masks out shapes, basically the same function as a gobo has for light.Instead of working with a virtual 3-D model, you work with multiple flat layers which mask individual surfaces of a form, but which are positioned, scaled and rotated in a 3d space.In some ways masking might seem an inferior method to mapping, but in most cases an audience wouldn ́t notice the difference, and it has many benefits when it comes to the actual process of making it, and the access to individual surfaces makes it possible to make interesting video textures.The main benefit is that you don ́t need to measure or calibrate anything. You place the projector and work with matching each layer to a different surface.