"Bald Eagle" <cre### [at] netscapenet> wrote:
>
> For what you're doing, I'd go for an orthographic camera, NO light, and an
> emission 1 white.

Yep, that is my current set-up. *Although*... That '3D slicer' app has some
interesting tricks among its more mysterious features, as I study and play with
it. To wit: Typical medical CT scans are basically grayscale files, from what I
have read so far. The various organs in the body produce different shades of
gray, depending on their density (and maybe other factors) as registered by the
X-rays from the rotating machine. There are controls in '3D slicer' to sequester
or specify which 'band' of gray that shows up as an object, and to eliminate the
other shades... essentially like the 'levels' and 'contrast' settings in
graphics apps. In fact, there are presets built-in for things like bones, etc--
based on some kind of accepted standard. SO, it would be possible to render
grayscale slices in POV-ray-- say, different grays for different parts of a CSG
object-- then use the app to 'remove' certain objects that you don't want to
print. Just an idea so far.
>
> I would say that your render settings such as image size ("resolution") and
> antialiasing values will have more of an effect than anything.

Exactly. In fact, the rez of the image slices seems to be more important than
the number of slices, for creating a sharp and detailed model. The many tests I
have made confirm this. I guess that's because the 3-D printing process is
mainly concerned with the quality of the outside shape-- in my case, the outline
of the solid white areas in the POV-ray images.

As far as antialiasing is concerned, I'm still not sure if it helps. AA is, in
effect, a tiny blurring of image pixels-- meaning grayscale in those tiny
areas-- and I don't yet know how '3D slicer' handles those. It's difficult to
see what effect it has on the final printed model, since the app's own
reconstructed model is so large that I have to shrink it down in the Cura
printing software...which 'tightens up' the quality and reduces any possible
oddness from the AA. But I am *still* making tests...and the printing process is
slow...
>
> Something extra wicked-cool would be to find a way to use a software
> to "unwrap" the skin of your object as a uv-map surface and just print a
> thin layer as triangles that could then be folded up into a "skin" that
> is the outer surface of your object.

I had the same idea! (well, at least the un-wrapping part.) So far, I haven't
seen such a feature in '3D slicer'... but that's not saying much! I have barely
scratched the surface of what it can do. It could probably make peanut-butter-
and-jelly sandwiches if I could find the controls...

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