Newbie needs help. Random 3d points in closed 3d space

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Permalink Reply by David Rutten on September 11, 2009 at 12:03pm

Hi Marco,

this is actually pretty tricky, because for every new point you insert, you have to test all the other points.

When I am confronted with a problem like this, the first thing I always do is try and find a way in which it cannot be done. If that sound backwards, bear with me. Once I know that there are cases in which a problem has no solutions, then I know what kind of problem it is likely to be. Algorithms that have to deal with potentially unsolvable problems are much, much harder to write and they typically require an awful lot of conditionals.

In your case, the might not be a solution. Distributing N points in a finite volume so that the minimum distance between all of them is at least x, will not work under the following circumstances:

N = 2
volume = 10x10x10
x = 20

And there's an infinite list of circumstances that also won't work.

---

That being said, I do think that IF you pick numbers that easily fit, this will be fairly easy to solve in VB.NET or C#. All you need is two nested loops, a dynamic list of partial solutions and a sh*tload of if...thens

Unfortunately all three of these things (loops, conditions and dynamic lists) are difficult if not impossible to do with the current version of Grasshopper.

If you are willing to go VB.NET on this I'll gladly help you out though.

--
David Rutten
david@mcneel.com
Seattle, WA

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Permalink Reply by David Rutten on September 12, 2009 at 4:48pm

I've written a small VB script that sort of solves this issue. But it's slow (really slow) and it might not find the best answer.

Definition file.

--
David Rutten
david@mcneel.com
Seattle, WA

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Permalink Reply by MarcO on September 12, 2009 at 5:13pm

Thanks a lot for looking into this
But somehow, I cannot download the definition, it says 'page not found'...

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Permalink Reply by David Rutten on September 12, 2009 at 6:21pm

Don't click on the link, that doesn't work (don't know why). Use the "Save Link As..." in the menu to get the file.

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Permalink Reply by MarcO on September 12, 2009 at 6:27pm

Thanks a lot, I'm gonna chack what's that like...

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Permalink Reply by voronoiii on September 13, 2009 at 6:20pm

Even right clicking and downloading is not working,..? could you download it,.?

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Permalink Reply by MarcO on September 14, 2009 at 4:10am

As it is said, you have to use "Save Link As..." that will work fine, but the definition won't open on my computer it seems to have a problem while reading or writing the file !!

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Permalink Reply by MarcO on September 14, 2009 at 6:31am

So I've downloaded the new version of grasshopper and it has quite usefull things in it such as proximity 3d which I used to resolve my problem.
I added a parameter so it is even more accurate as what I wanted.
It works like this:
- The intervall is -75 to 75 but can of course be easily changed !!
- there are 3 sliders to control randomness of point picking
- there are two sliders to control distance between points (minimum and maximum)
Lines only show between points if all points are between range!!

Here is the definition, if you have any ideas or ways to make it better please tell me !!


P.S: Maybe it is a little bit strange definition but it's my first attempt to do something over than tutorials!!

Attachments:

• field try 101.ghx, 185 KB

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Permalink Reply by Theunis du Toit on September 14, 2009 at 10:51am

Sorry? Proximity 3d? Where in GH is it, or what version did you download where?

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Permalink Reply by MarcO on September 14, 2009 at 12:14pm

http://www.grasshopper3d.com/page/next-build this the latest version on this verry website.

and you can right double click to get the search dialog box and type proximity...

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