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Topic: How to make weighted random numbers?
Replies: 7   Last Post: Feb 28, 2009 3:49 AM

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swp

Posts: 9
Registered: 10/3/05
Re: How to make weighted random numbers?
Posted: Feb 27, 2009 10:21 PM
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On Feb 27, 9:36 pm, Rich Grise <r...@example.net> wrote:
> Say, I want to fill a sphere uniformly with random dots; the logical way
> to do that in r,theta format; otherwise to make a sphere, you'd have to
> do  some heroic math on the three dimension (or is there some
> quick-n-dirty formula that can do it in one flop, that they don't tell
> us high school (and Tech School, don't forget!) ?
>
> Either way. I don't want a uniform sphere - more like density through the
> center looks like a bell-shaped curve, i.e., denser in the middle?
>
> It's got to be computable, maybe with iterations, but that's what I
> do best! I just have no idea what the algorithm would be.
>
> What I'm up to is I have a 3-d drafting program and I want to approximate
> a translucent ball effect. I can enter coordinates by copying the output
> and paste it into the command line to automatically place n dots. ;-)
>
> Thanks!
> Rich


http://mathworld.wolfram.com/Sphere.html has a good discussion of the
math, and links to the math for intersections of various shapes with
each other. I believe those can lead you to the proper math for your
desired effect. Of course, I could be way off base also.

swp



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