Lost in mathematics with Projector node

vvvv beta general
1

Hi
concerning the node Projector, it needs a Distance/Width, but usually projectors’ specs come in the Distance/Diagonal format, now add the zoom capability of any projector and I get lost in the calculations. Any help?
My projector is Optoma EX762
Projection Distance 3.9ft. ~ 39.4ft. (1.19m ~ 12.01m)
Projection Mode Front, Rear, Ceiling
Projection Screen Size (Diagonal) 30in. ~ 369in. (76.2cm ~ 937.26cm)
Throw Ratio 1.6 ~ 1.92:1

Also is the 16:9 pin supposed to be set to 0 in this case?

tx
Simone

2

your aspect ratio is 4/3 (1024/768), so i figure 16:9 should be 0.
width of the image can be calculated from the diagonal:
angle alpha=arctan(3/4) (36.87°)
width=diagcos(alpha)=diag0.8

also, distance/width already is the throw ratio, but pay attention, some may calculate it with the diagonal.

3

aha! So I was ok with the values given by the tech specs.
Thanks