tan(angle) will get you the slope of your camera angle. Multiply that by the distance and zscale to get the z height at any given distance. Remember to also add the z height of the origin/camera as well.
Thanks for your response! Your solution will work with raytrace, but what I am trying to achieve is to make flying visible bullet, which may be a little harder to implement.
I tried multiplying bullet's Z elevation by 3DCamera's LookZ every tick, but it seems to be wrong. Any ideas?