exactly.

this is to compute the focal point within the projector. (which is also dependent of the lens position & depth, the zoom ratio and the depth of the projector).

As a result of this the projector can compute the focal point within the world and can setup the view transformation.

however it luckily turns out to be the parameter with the smallest impact on the projection. having a wrong value here only results in a small error.

having error in rebuilding a real environment has to be totally expected. Reduce the number of uncertaincies to get better results.

However we should do a list of priorities which parameters should be checked first:

- Zoom Ratio
- Shift
- Position & Rotation of Projector and Architecture
- Geometry of Architecture

On the other side most of the projector parameters can be meassured best when it doesn’t hang below the ceiling yet. Enter those values once to get realistic iconographic representations in your scene overview renderer…