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### Convex hull in 3D

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```I'm pretty sure that a few years ago I downloaded a function that Eric
W. wrote to compute the CH of some points in 3D. He intended it to be a
temporary solution because Mathematica has CH only for 2D. I can't find it now
and I need it. I have only a dozen or so random points and don't need
super speed.

Steve Gray

```
 0
Reply S 8/6/2010 10:59:05 AM

See related articles to this posting

```This seems to work, watch out for: ?*`Convex*

pts = RandomReal[{-1, 1}, {100, 3}];
hull = ComputationalGeometry`Methods`ConvexHull3D[pts];
Graphics3D[{PointSize[Large], Point[pts], White, Opacity[0.5],
hull[[1]]}]

HTH,
Yves

Am 06.08.2010 12:59, schrieb S. B. Gray:
> I'm pretty sure that a few years ago I downloaded a function that Eric
> W. wrote to compute the CH of some points in 3D. He intended it to be a
> temporary solution because Mathematica has CH only for 2D. I can't find it now
> and I need it. I have only a dozen or so random points and don't need
> super speed.
>
> Steve Gray
>

```
 0
Reply Yves 8/7/2010 5:32:52 AM

```In article <i3gptp\$35i\$1@smc.vnet.net>,
"S. B. Gray" <stevebg@ROADRUNNER.COM> wrote:

> I'm pretty sure that a few years ago I downloaded a function that Eric
> W. wrote to compute the CH of some points in 3D. He intended it to be a
> temporary solution because Mathematica has CH only for 2D. I can't find it
> now
> and I need it. I have only a dozen or so random points and don't need
> super speed.
>
> Steve Gray

I submitted a set of packages for multidimensionl convex polyhedra to
the Wolfram Library Archive:
<http://library.wolfram.com/infocenter/MathSource/7034/>
I would advise that you convert your coordinates to rational numbers.
Then I think it would handle the problem you describe with satisfactory
speed.

--
Christopher J. Henrich
chenrich@monmouth.com
http://www.mathinteract.com
"A bad analogy is like a leaky screwdriver." -- Boon

```
 0
Reply Christopher 8/9/2010 9:14:40 AM

2 Replies
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