Hi there!

As a warning in advance: I'm a pretty inexperienced Povray user, that has only
done the typical tutorial-like stuff up to now.
However, I've seen pretty amazing things done with the DF3 density files, which
I want to use to visualize some potential landscapes of certain molecules. What
I eventually want to do, is to input a certain array of coordinates and (somehow
scaled to that integer values up to 255) potential values, which then should be
converted into such a DF3 file. That I want to use to produce "cloud-like"
structures with different colors (similar to here:
http://www.stanford.edu/~fenn/povscript/df3.html)

Is that possible and are these steps at least in principle correct?
I spend all day looking for some kind of "easy" tutorial, but wasn't all that
succesfull :(
I found some DF3 maker tools, but I still haven't understood that DF3 format and
its usage completely. Searching these newsgroups I found the hint, that the beta
version somehow has an "ARRAYS_WriteDF3" macro in the arrays.inc.
However my knowledge is unfortunately not big enough, to know how to use this :(

I'd be really glad, if someone could help me understand and use this very
promising feature of povray.

greetz angura

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> Hi there!
>
> As a warning in advance: I'm a pretty inexperienced Povray user, that has only
> done the typical tutorial-like stuff up to now.
> However, I've seen pretty amazing things done with the DF3 density files, which
> I want to use to visualize some potential landscapes of certain molecules. What
> I eventually want to do, is to input a certain array of coordinates and (somehow
> scaled to that integer values up to 255) potential values, which then should be
> converted into such a DF3 file. That I want to use to produce "cloud-like"
> structures with different colors (similar to here:
> http://www.stanford.edu/~fenn/povscript/df3.html)
>
> Is that possible and are these steps at least in principle correct?
> I spend all day looking for some kind of "easy" tutorial, but wasn't all that
> succesfull :(
> I found some DF3 maker tools, but I still haven't understood that DF3 format and
> its usage completely. Searching these newsgroups I found the hint, that the beta
> version somehow has an "ARRAYS_WriteDF3" macro in the arrays.inc.
> However my knowledge is unfortunately not big enough, to know how to use this :(
>
> I'd be really glad, if someone could help me understand and use this very
> promising feature of povray.
>
> greetz angura
>
>
>

The renderings shown use relatively low resolution DF3's.
They also show some objects that lies within the confine of the density 
files.

What you need to have various colours is to use a colour map to assign 
some coloration to ranges of values.
You can have more than one media in a single container. It can be used 
to have different colours.

Take the time to read all the informations about media. Also, do all the 
media tutorials and samples. Once you have rendered a sample, change 
some part of it, one at a time, and see how it changes the resulting image.


There are gross inacuracies in the text. For example, at the bottom it 
says: "Make sure all the lights in your povray scene are shadowless - 
the bounding box of the df3 file tends to refract some light, even 
though its declared as a hollow object."
That's bogus.
ANY object with a pigment of rgbt 1 will be totaly invisible. It just 
CAN'T refract light _unless_ you set an ior for it. To make such an 
object visible, you must add some highlighting, reflection or an ior.
"hollow" only enable an object to contain a media, nothing else.


Take note that the text is VERY dated. It was good for version 3.1 or 
older (over 10 years ago). The media should ONLY use 1 intervals (the 
default value) and the intervals keyword should be absent.
The samples value only use a single value, the first one. That value 
MUST be at least 3. You often need larger value for that.


Alain

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