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Thread: "Five Point Sphere"/ "3 point circle"

  1. #1
    Axes grinder- Dongle #99
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    "Five Point Sphere"/ "3 point circle"

    Lookin' around for two plugins:

    I found this one: select 3 points, and it creates a circle that passes thru those three points.

    The other one I'm looking for does the same thing, but for spheres, and I believe it requires 5 points ....although shouldn't 4 be enough?)
    They only call it 'class warfare' when we fight back.
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  2. #2
    NewTek Developer jameswillmott's Avatar
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    Quote Originally Posted by jeric_synergy View Post
    Lookin' around for two plugins:

    I found this one: select 3 points, and it creates a circle that passes thru those three points.

    The other one I'm looking for does the same thing, but for spheres, and I believe it requires 5 points ....although shouldn't 4 be enough?)
    Yes, I believe 4 should be enough...
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  3. #3
    Registered User john_the_blind's Avatar
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    Not sure...if you have a perfect 4 vertex poly, there are a lot of possibility of sphere...but with a 5th vertex...

  4. #4
    well, in that case for any cyclic N vertex poly you'll have many possibilities for creating a sphere.

  5. #5
    Axes grinder- Dongle #99
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    Usually these routines insist that there be vertex that is not coplanar with more than 3 others.

    Any given 3 vertices can define a circle. Throw in another that is not coplanar with the first 3 and you define a sphere.

    And I'm still looking for that plugin.
    They only call it 'class warfare' when we fight back.
    Praise to Buddha! #resist
    Chard's Credo-"Documentation is PART of the Interface"
    Film the cops. Always FILM THE COPS. Use this app.

  6. #6
    Where did you find the 3 point to circle plugin. I was looking for something like that the other day.
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  7. #7
    Axes grinder- Dongle #99
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    It was on, and by, Kevin MacPhail's site.

    The math for a 4 point sphere involves matrices. ::shudder::
    They only call it 'class warfare' when we fight back.
    Praise to Buddha! #resist
    Chard's Credo-"Documentation is PART of the Interface"
    Film the cops. Always FILM THE COPS. Use this app.

  8. #8
    Thanks
    iMac 27" Quad Core 2.8 i7
    ATI Radeon HD 4850, Mountain Lion 10.8.2

  9. #9
    If you guys can't find a plugin that does 4 point sphere (maybe LWCad can do it?) I could probably create a quick lscript for that... I think.

  10. #10
    Axes grinder- Dongle #99
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    Quote Originally Posted by art View Post
    If you guys can't find a plugin that does 4 point sphere (maybe LWCad can do it?) I could probably create a quick lscript for that... I think.
    LOL. We shall see: search the page for "Four points are sufficient":

    Wolfram!

    I remember the old routine was instantaneous: I'm not sure how fast all this math will get executed in LScript.

    +++++++
    Oh, now I found the one I originally saw...
    They only call it 'class warfare' when we fight back.
    Praise to Buddha! #resist
    Chard's Credo-"Documentation is PART of the Interface"
    Film the cops. Always FILM THE COPS. Use this app.

  11. #11
    Scene Destroyer DrStrik9's Avatar
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    Quote Originally Posted by art View Post
    If you guys can't find a plugin that does 4 point sphere (maybe LWCad can do it?) I could probably create a quick lscript for that... I think.
    Yes, please. I'm finding that nothing works here except UB plugins ending in .plugin, and good ol' lscript, which always works, and seems to be pretty solidly cross-platform.

  12. #12
    Super Member Red_Oddity's Avatar
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    The link Jeric posted has a piece of C code there as well, which i think can quite easily be adapted to LScript or a plugin.

    I'm quite busy at the moment, but i still have some Phantom super slow mo shots to convert, might give it a try when those are converting.
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  13. #13
    Registered User Kuzey's Avatar
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    Edit: never mind...I was thinking of something else.

    Kuzey

  14. #14
    I've been to that site before (Paul Bourke's) and they have plenty of useful stuff for 3d math. As Red Oddity said, converting that C code should be very straightforward. I can try to do it this evening unless he beats be to it

  15. #15
    Super Member Red_Oddity's Avatar
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    Took a quick look at it, seems very doable, it looks like removing the memory allocation and initial sphere setup are the only things that need to be removed and some variables need to be declared (like the multidimensional arrays).
    I have no special talents. I am only passionately curious. - Albert Einstein
    visit my company site : House of Secrets
    visit my personal site : svenneve.com

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