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On 5 Oct 2000 06:55:44 -0400, Warp wrote:
>Chris Huff <chr### [at] mac com> wrote:
>: An isosurface can do nearly every primitive in POV-Ray, and
>: many other shapes.
>
> Good that you said "nearly" because isosurfaces can't do _every_ primitive
>in povray.
>
> Quiz: Which primitive or primitives it can't create at all?
Among others, julia and mesh. (Well, mesh might be possible but it would be
ugly.)
> Which primitive or primitives it can create only partially?
planes, polys, anything infinite.
--
Ron Parker http://www2.fwi.com/~parkerr/traces.html
My opinions. Mine. Not anyone else's.
Proudly not helping RIAA and SDMI steal my rights --
http://www.eff.org/Misc/EFF/Newsletters/EFFector/HTML/effect13.08.html
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Simon Lemieux <lem### [at] yahoocom> wrote:
>> I'd say make a script to generate triangle meshes, use isosurfaces (requires
MegaPOV from
>> nathan.kopp.com), or (for the cylinders only) a torical section; if you need math
help let
>> me know.
> Yes this is good, I would actually make a C++ program for this, as I usually
> do...
> But, I forgot to say about interior... it is being discussed in
> povray.advanced-user and as I know a bunch of triangles togheter won't have a
> proper interior... which will be important as soon as I get a curver cylinder,
> this is my next step, I forgot to mention it...
> I think the best way to do it is still to put a few cylinders togheter and curve
> them myself... the junction could be made with an intersection of the two
> segments and the union of the two segments themselves, etc...
> What do you think?
I think a sphere sweep might be your perfect solution. Assuming you can
compute the points that the cylinder begins and ends and intermediate
points, this will give exactly the effect you want if you use one of the
splines. Even if you don't use a spline function, it should be cleaner than
using a lot of cone segments as the edges won't be visible.
Best of all, since each has a radius, it'll work for your cones too.
And finally, you won't have to do a merge to get rid of internal surfaces,
since the sweep would be a single object.
Geoff
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Geoff Wedig wrote:
> I think a sphere sweep might be your perfect solution. Assuming you can
> compute the points that the cylinder begins and ends and intermediate
> points, this will give exactly the effect you want if you use one of the
> splines. Even if you don't use a spline function, it should be cleaner than
> using a lot of cone segments as the edges won't be visible.
>
For the record, here is a croissant-making isosurface I posted in p.advanced-users
some time ago.
#declare major_axis=5;
#declare minor_axis=1;
#declare a=function{sqrt(x^2+z^2)-major_axis}
isosurface{
function{sqrt(y^2+a^2)-minor_axis*(0.9+z*0.2)}
contained_by{sphere{0,10}}
eval
threshold 0
pigment{Red}
rotate y*45
}
G.
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