Hello!

I noticed something strange about the way POV-Ray handles transmit values.

I wrote about it in the thread "transmit > 1 ?", but I didn't get so many
replies to my questions, so I try again.

To show what I'm talking about I have made some graphs. You can see them in
povray.binaries.images .

They show the strange way POV-Ray handles transmit values above 1. I know
that a transmit value above one (or below zero) is an unrealistic thing, but
it can be used for useful special effects. POV-Ray handles transmit values
in a certain mathematically way. That is true for transmit values between 0
and 1 but also for negative values. The way POV-Ray handles such transmit
values is fully logical and predictable if you understand it. The problem is
that POV-Ray handles transmit values above 1 in another way, and that is
very annoying. I think POV-Ray simply ignores the color of the surface when
the transmit value of the surface is above 1. But I think it shouldn't
ignore it. If for example a transmit value of 1.3 is present, the color of
the surface should be multiplied with -0.3 because the surface color is
normally always multiplied with ( 1 - transmit_value ).

Anyway, my point is that POV-Ray should be changed so it handles transmit
values above one in the same way as it handles other transmit values. It may
not be intuitive, but the present method isn't intuitive either. The
advanced user will benefit from the change.

Greetings,

Rune

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