"Bob Hughes" wrote:
> I care, really I do  ;-)

:-)

> Thing is I guess is that transmit is somehow
> intended to, well, transmit. Something akin
> to emission in media let's say.

What I complain about that the color of the surface is ignored. And for a
strange reason it is *only* ignored with transmit values above 1. It
shouldn't ever be ignored.

> Whether that's right or wrong is up to the
> POV gods I suppose. You're right though, it's
> something which doesn't seem to adhere to a
> pure transparency sort of thing as it appears
> to be doing within the confines of only a 0 to
> 1 range.

No, my point is that actually it works "correctly" with *all* values below
1. Even negative values. Transmit values above 1 should simply work just the
same way.

> It seems the rgb 0 (or blacker) end of the
> spectrum is given a certain priority.  I don't
> know if I'm wording any of this very well.

Normally the color you see when looking at a transmitting surface is
transmit_value * color_behind_surface + ( 1 - transmit_value ) *
surface_color

That is true for all transmit values below 1. But transmit values above one
is handled differently:
transmit_value * color_behind_surface

That is, the surface color is totally ignored.
At least I *think* it works that way. It seems so.

Currently there's some certain useful effects you can't achieve. If my
suggestion is followed, these effects would be possible to achieve, and in
most cases you would still be able to achieve the old (current) effects too.

I know that my suggestion is not intuitive, but the current method isn't
intuitive either. When using transmit values above 1 one should expect
intuitive results at all.

Furthermore, if the transmit code in POV-Ray works the way I think it works,
then following my suggestion would not require any new code. Only some
existing code should be removed. Something similar to a #if statement I
guess. Instead of using one formula for transmit values below one and
another for transmit values above one, the same formula should be used for
all transmit values. Simple and logical I think.

> Did you also try graphing 'filter' in this
> same way? Talk about something that emits
> when >1 !

I didn't try graph that. Maybe I should...

> Anyhow, very good job of graphing.

Thanks!

Now I just hope some POV programmers or patch makers will look at the
problem, or at least reply here...

Greetings,

Rune

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