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    Geosphere?

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    • T Offline
      tml
      last edited by

      @thomthom said:

      I'm looking to generate the points for the sphere on the right.

      Start with a octahedron, divide each edge into half and thus each face into four equal smaller triangles, move the new vertices to the desired radius, repeat.

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      • T Offline
        tml
        last edited by

        Note that the above results in just a fairly nice approximation, though. (And I don't know if it matches the subdivision used in your example image.) Only for the (not really sphere-like, as they have so few faces) Platonic solids are the vertices in a strict sense evenly distributed, though. See http://www.cgafaq.info/wiki/Evenly_distributed_points_on_sphere and especially http://www.math.niu.edu/~rusin/known-math/95/sphere.faq .

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        • thomthomT Offline
          thomthom
          last edited by

          Approximation is ok. Just just want to take a fixed number of points and distribute them approximately evenly. Doesn't matter if they need to be rounded to a number that fit some geometric restriction.

          Thanks for the links - I'll look into them.

          Thomas Thomassen β€” SketchUp Monkey & Coding addict
          List of my plugins and link to the CookieWare fund

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          • thomthomT Offline
            thomthom
            last edited by

            Excellent - the spiral methods works great for my use! πŸ‘

            Thomas Thomassen β€” SketchUp Monkey & Coding addict
            List of my plugins and link to the CookieWare fund

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            • AdamBA Offline
              AdamB
              last edited by

              Its pretty common to subdivide a cube and then project onto a sphere.

              If you want evenly distributed but not a regular mesh, you could use a Hammersley point set.

              Developer of LightUp Click for website

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              • thomthomT Offline
                thomthom
                last edited by

                @adamb said:

                Its pretty common to subdivide a cube and then project onto a sphere.

                Would that give a even-ish distribution?

                @adamb said:

                If you want evenly distributed but not a regular mesh, you could use a Hammersley point set.

                Thanks for the pointer - will look it up. πŸ‘

                Thomas Thomassen β€” SketchUp Monkey & Coding addict
                List of my plugins and link to the CookieWare fund

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                • david_hD Offline
                  david_h
                  last edited by

                  @unknownuser said:

                  A sphere with a center (x0,y0,z0) with diameter r
                  has all points x,y,z like

                  http://upload.wikimedia.org/math/3/3/0/33031c82e871501422b05455c81d2680.png

                  with

                  http://upload.wikimedia.org/math/e/b/9/eb91f8174391d023015dedf9beb94e5d.png

                  http://upload.wikimedia.org/math/9/0/1/9011474548ae3216019a280ff95d25a3.png
                  = Latitude

                  http://upload.wikimedia.org/math/1/9/6/1964adc54d7dc608fd9f63a46cae422b.png
                  = longitude

                  That is just how I would do it! πŸ˜’ πŸ’š

                  If I make it look easy...It is probably easy

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                  • pilouP Offline
                    pilou
                    last edited by

                    Me too πŸ˜„

                    Frenchy Pilou
                    Is beautiful that please without concept!
                    My Little site :)

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                    • thomthomT Offline
                      thomthom
                      last edited by

                      Google are really quick to index this site!
                      I did a search for "Hammersley point set sphere" and this thread came up as #3 already. πŸ˜’

                      Thomas Thomassen β€” SketchUp Monkey & Coding addict
                      List of my plugins and link to the CookieWare fund

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                      • mitcorbM Offline
                        mitcorb
                        last edited by

                        Not busy enough elsewhere, eh tml?
                        Thank you for your talents, also.

                        I take the slow, deliberate approach in my aimless wandering.

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                        • AdamBA Offline
                          AdamB
                          last edited by

                          There you go.

                          http://forums.sketchucation.com/viewtopic.php?f=180&t=30694&p=269864#p269864

                          Developer of LightUp Click for website

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