William F Pokorny <ano### [at] anonymousorg> wrote:
> On 11/3/23 12:49, Mike Miller wrote:
> > I've run into a problem with the
> > transparent portion of the png when turning on fog. The fog is tinting the
> > billboard shape.
>
> The fog feature is a faked effect which works, solely, with initial
> camera rays. More specifically fog is added using the distance from the
> camera to the first intersection - or effective infinity (2,000,000
> units?). Those initial camera rays will intersect the billboards whether
> the pigment is transparent or not.
>
> So, I'm not surprised the bill board tint is different, but at this
> moment, I don't understand why it appears to be more foggy rather than
> less. Most probably your fog is set up to be more dense at distance (not
> ground fog)?
>
> Maybe we'd get what you see, if using ground fog that is not oriented
> correctly? Not sure. Could be some bug too - there are some in the
> official POV-Ray code - and probably some unknown ones still in my
> playpen code too. Faked effects are tricky.
>
> In any case, distance based features will struggle with a "billboards
> technique".
>
> Bill P.

Thanks Bill,
I'll mess around with it a bit more before giving up. I'll let you know if I
find a solution before using triangle mesh for these plants. :)
Best regards,
Mike.

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