Frank nous apporta ses lumieres en ce 2008/02/22 09:25:
> I have a 3D voxel image of 256 by 256 by 256 voxels of a heart, which is already
> segmented. Let's assume that the left ventricle is marked by a 1 in the image,
> the right ventricle by a 2, the outside by a 0. I would like to render the
> geometry in povray, with the surface of the segments smoothed out, left
> ventricle in blue, right in red. I need reflection on the surface, meaning I
> want to define a solid object.
> 
> I could produce a geometry file that contains lots of small boxes given with
> their full dimensions, and unite them for the respective objects, or a massive
> number of blobs - but that seems uneffective, and I failed to create a smooth
> (!) volume from these blocks anyway.
> 
> Any suggestions? I couldn't find a simple object that does what I need. Maybe it
> can be done with a density file? I tried to, but couldn't get reflections on the
> surface to work.
> 
> Frank
> 
> 
> 
You can use that as a density pattern usine a color_map set with the correct 
values. Apply that pattern to an emissive media.
This method will give you a transparent volumetric rendering: you will see the 
interior. As there is no real surface, you won't reflect anything. It's like 
trying to get a reflection on some gaz.

You can scan the data and create a blob. Place a small sphere component for all 
non-zero voxels. Each blob components will receive a pigment depending on the 
value of the voxel they represent. If the inside of the cavities are zero as the 
exterior, they will be open. Experiment with the threshold value, and the 
components radius and strength until you get an acceptable result.
The resulting object can be made reflective. You won't see the internal parts.

You can combine both: Make the blob, make it transparent with some reflection in 
the finish, add "hollow" and fill it with some media modulated with the density 
file.

-- 
Alain
-------------------------------------------------
Presbyterian: This shit was bound to happen.

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