"cbpypov" <nomail@nomail> wrote:
> What I forgot: I turned on radiosity as yoou mentioned but without a light
> source the image was black, except for the emitters (if using a black
> background). Why is that?

Because those are the only things that emit any light.  If you need a light
source, then define a thing - a light panel (box{}) a tube (cylinder{}) a CSG
lightbulb, etc. that has an emission value.  The stronger the emission, the more
light.  You may need to define diffuse or specular in a finish block for your
other objects to reflect light back to the camera and make them more visible.

Let's say I read that file in and
> generate an array from it:
.....
> Now the array `Field_values` holds all the points and the respective
> intensities.
.....
>
> here, `Field_value_interpolated` has to be a function that connects the x,y,z
> coordinate to the `Field_intensity` in the `Field_values` array given above.

Well, you're kinda going around in a circle - if you have _data_ then you should
use that to create a df3 file - voxels.  IIRC POV-Ray has different ways of
interpolating based on those (trilinear, tricubic, etc.)

> Moreover, what are the x,y,z that the density function passes?

POV-Ray will evaluate your density "function" based on all of the x, y, and z
coordinates in the unit cube that the media occupies.

See my re-invention of POV-Ray's isosurface "wheel":
http://news.povray.org/povray.binaries.images/thread/%3Cweb.59cf0d20e6e56be5cafe28e0%40news.povray.org%3E/

Most notably the x, y, z nested loops at the end of the code.

My idea was that if you were generating the data in your CSV file with an
equation, then you could bypass all that and just use that equation as your
density function directly.  But I don't know all of the details of how you're
putting this together - I have no "bigger picture" yet.

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