Those functions are meant for stereo display, but since I don't have the proper hardware I haven't tested them thoroughly. I think they're not your best bet.

thanx. but i actually "just" want to project an image of a virtual object onto it's real representation.
so let's say we have a teapot, and project this onto a teapot. so then we can play with texture distord the mesh, and it looks like the real teapot is changing skins.
just the really basic projection mapping, but on complex surfaces(objects).

So my question was more leading to, how can I calculate the distortion.
If I am far away with the beamer, the beamer sees something else and needs to project something else then from really close.

I came across these handy functions withing the proscene library now:

scene.camera().setFieldOfView() ;
scene.camera().setFocusDistance();

which basically does the job for me.
In field of view I enter the beamer's projection angle, which is calculated via pythagoras with the distance and height of the projected Image.
And the distance to the object in focus Distance.

Then we get an almost perfect alignment of real and virtual 3D image.


And to answer my initial question too,
yes i was on the wrong track.
we don't need to but in the actual real world data.

all that counts is that everything is in same proportions.
the distortion will be/is same for a 3cm distance to a 1cm screen and a 3000km distance to a 1000km screen.

I'm glad to hear that you found your way with these two methods.

I'll post a link as soon as it's there!

Should check out kyle mcdonalds git hub. He created a set of tools for setting up a projection mapping gig.