JC (Exether) wrote:
>If I get it right, it seems to me that the base of the problem is that
>POVRay uses indirect coordinate system (left hand), but it is not enough
>to take z as the up direction, you should take -z. In a direct
>coordinate system (u, v, w), the w vector should see u->v in the
>trigonometric way (which is counter clock). Putting "-" in the right
>places in your formulas should do it.
>
>JC
>

Actually, you want up to be +z, to be consistent with physics.  Depending on
whether you do x or y as the "right" axis, you would have the following:

up z, right x, direction y
or
up z, right y, direction -x

The latter of the two is nice in that it is just a basic rotation (i.e.
quandrant I is in the same location) of the right-handed POV-Ray system: up
y, right x, dir -z.  Just replace x with y, y with z, and z with x.

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