L3P -ca<a>   the Camera Angle option

The Camera Angle option lets you set the camera viewing angle. The viewing angle is the top angle of the pyramid described in the L3 globe section. The camera viewing angle is the horizontal one. The default is 67.38 degrees = 2*atan(2/3). Because of the 4/3 aspect ratio, the vertical viewing angle is: 2*atan(1/2) = 53.13 degrees. The 4/3 aspect ratio is always maintained even if the (horizontal) camera viewing angle is changed. The vertical camera viewing angle is 2*atan(tan(a/2)/(4/3)).

L3P's automatic camera positioning will always move the camera as close as possible to the model (unless you specify the distance (radius) in the -cg option or use the -cc option). Therefore the higher angle, the wider camera angle, the camera is moved even closer and you will get a fish-eye effect, the model will be "distorted". The lower angle, the camera viewing pyramid gets narrower, the camera must be moved away to still have the model fit into the viewing angle, and you will see that the model looses perspective.
Camera angle 10 degrees
l3p m6596a -b -f -ca10 
Camera angle: 10° 
Camera distance: 1771
Camera angle 37 degrees
l3p m6596a -b -f -ca37 
Camera angle: 37° 
Camera distance: 477
Camera angle 67.38 degrees
l3p m6596a -b -f 
Camera angle: 67.38° (default) 
Camera distance: 248
Camera angle 97 degrees
l3p m6596a -b -f -ca97 
Camera angle: 97° 
Camera distance: 158
The difference in the lighting in the scenes above is because the lights are placed at the same distance from the model as the camera.

L3P main page
Lars C. Hassing's Homepage

Last updated December 12, 1998