"Kenneth" <kdw### [at] gmailcom> wrote:
> I appreciate your effort. I need to digest them, to see which
> ones are feasible (with my coding skills!), and which ones are out of my depth.

If you're putting in the serious work to make a tool / tutorial like this, then
feel free to just flat-out ask, "Hey, can you code me up something that does...
x,y,z?"


> I like that idea. If I go that route, I'll make another complete tester scene
> and post it separately. Then the one here can be thought of as a kind of
> 'first-step' or introduction to media/color interaction effects.

Or a last-step in the parameter selection flow to see it on a larger scale.


> I did initially inclue a caption (for one media permutation, anyway) but
> eliminated that to make the code example shorter and not-so-complex. But it's a
> very good idea. I'll work on that. As far as the vector stuff goes, I'm
> definitely out of my depth.

Well, it got _really_ interesting a while back:
http://news.povray.org/povray.advanced-users/thread/%3Cweb.577e597b5ff2a8e65e7df57c0%40news.povray.org%3E/?mtop=409379


> > I'd also include a _grayscale_ long-box.
> >
> The color of the embedded box can actually be switched to gray (it's a
> commented-out pigment in the code); but yes, it would be better to have a
> 'switch' to change between that and the current red-green-blue pigment.

Oh, well, I'm a hog - I'd want it all in the same scene at once.  :)

> > And maybe a light source...
> >
> There's actually a light already in the scene; but perhaps you mean a spotlight
> aimed *at* the media, to see the effects? (Another idea would be to put a light
> *inside* the media, shining outwards-- that always looks cool ;-) )

Yes, the light source INSIDE the media was what I was thinking.
I think we can safely assume that most light sources outside the media would be
easy to imagine.


> Alas, the trouble with making media objects is that there are so MANY
> permutations of settings that can be chosen-- color, density amount, the density
> PATTERN itself, the combinations of different medias-- that it boils down to
> 'user preference'-- even for one particular effect. However...

Right, but I'm imagining this as more of an automated demonstration tool, rather
than a template for making a media-filled object.
To some degree, I envision things like this "pointing" or suggesting in some
way, all of the possible paths one might take - be it the rendered image itself,
a caption, a link to further reading in the code comments, a comment, or a list
of commented-out or #case-switch-break-end examples of how all of the code might
possibly be implemented.


> ..... that's a good idea. I was actually going to include a few examples ....
Trouble is, some examples may end up be
ing non-trivial 'test scenes'
> themselves!

Indeed.  The sheer complexity of covering just an "adequate" number of cases /
permutations became immediately apparent as I thought about "blocking it out" -
you'd need an n-dimensional space, or a fairly long animation sequence that
cycled through a number of permutations.

Perhaps a scene could be constructed such that given the maximum number of sane
attributes to vary, it would cycle through THOSE values in the .ini animation.
That way any given permutation of _only the selected subset of possibilities_
would be rendered.  But the whole range of values that could be played with in
combination could be implied.
Then they could all be put together manually in something like your current test
scene.

Some combinations might benefit from a ternary plot.
https://en.wikipedia.org/wiki/Ternary_plot


> I guess I need to write a book too ;-)  (Kidding.) The idea is excellent.

Adams seemed to me like someone who was "a scientist, who just happened to have
photography as his subject of study."

Not to make this any more complex, but as it's in my my mind, I'll mention/ask
it.  Can media have pigments/textures that have filter / transmit /
_reflectance_?

> Sounds
> like there needs to be a *collection* of 'media tester scenes', each showing a
> particular and separate kind of effect... to help guide the user to an
> understanding of how to achieve it. (Unfortunately, media experimentation is a....

Yes, just perusing the media documentation suggests that perhaps a suite of
scenes might be necessary to adequately address the topic.

I'd say that this is an instance where certain caveats and pitfalls could be
addressed programatically due to the complexity of media.

"The question of whether the program should scale the density of the media with
the object is a question of interpretation: For example, if you have a glass of
colored water, a larger glass of colored water will be more colored because the
light travels a larger distance. This is how POV-Ray behaves. Sometimes,
however, the object needs to be scaled so that the media does not change; in
this case the media color needs to be scaled inversely."

So perhaps generate a media-filled container using a macro, and then use a Scale
variable to scale the container, and divide the color.  Also spit out a short
blurb to the #debug stream.
"Scale > 1.0  Adjusting media color to maintain constant intensity."
or some such.
Make_Container (blah, foo, bar, Scale)
{
scale Scale
color rgb <R, G, B> / Scale
#debug "Scale > 1.0  Adjusting media color to maintain constant intensity. \n"
}

I might try to search and see what sorts of media are the most commonly
requested / used

Post a reply to this message