Best way to design a hexagon with increasing angles on sides?

Discussion in 'Design and Modeling' started by prismspecs, Mar 18, 2013.

  1. prismspecs
    prismspecs New Member
    I want to create a 3d hexagon with a bit of a twist. The top face is exactly a hexagon, but each side has an angle starting at.. let's say 170degree (flaring out at the bottom. So 180 here is straight down). So the first of the six sides is 170, the 2nd is 167, the 3rd is 164 and so on. I realize that there must be an additional plane connecting the side faces to maintain a flat angle on all sides. Any ideas on how I might accomplish this one?
     
  2. stonysmith
    stonysmith Well-Known Member Moderator
    May I suggest that you take a look at OpenSCAD? (www.openscad.org)
    This bit of code:

    $fn=6;
    r=[0,1,2,3,5,8,13,21,34,55,89];
    for (i=[1:10]) {
    translate([0,0,i])cylinder(r1=10+r[i-1]/10,r2=10+r/10,h=1 ,center=true);
    }

    would produce this:
    pyramid.jpg
     
  3. JACANT
    JACANT Well-Known Member
    It depends on what software you are using. This was done in Sketchup by making vertical faces down from the top, then rotating each one in turn. I then extended the vertical lines to meet the ground plane. Then joined the end points together.
    http://skfb.ly/5kj3hf1d0
    Reminds me of a 'Dalek'
     

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    Last edited: Mar 18, 2013
  4. prismspecs
    prismspecs New Member
    Woah, thanks fellas! That programmers shape builder is pretty interesting. I'll also have to check out sketchup. I should have been a bit more clear about my model, which I've nearly completed. If anyone has time to check out the attachment, I have a question.

    You'll see that the top is a 6 sided face, the bottom 12 sided. This way the bottom can flare out, and each of the larger bottom edges are to be increasingly titled. Starting at nearly straight up and down, 180 deg, and increasing maybe 2 or 3 deg per edge. I have more or less accomplished this by grabbing the edges in ortho top view and dragging them along the y axis by increasing amounts, then rotating the entire mesh in edit mode, and moving on to the next edge. I'd prefer to do it with angles rather than guessing with grab, is there a way to do that?

     

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  5. JACANT
    JACANT Well-Known Member
    I did this originally but thought you only wanted six sides not twelve.

    hexagon shape2.png
     

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  6. prismspecs
    prismspecs New Member
    Beautiful!
    For the sake of learning, can I ask why this shape I made doesn't seem to be solid? When I do a difference modifier it won't respond correctly.
     

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  7. Keymaker
    Keymaker Well-Known Member
    1. your normal where wrong (ctrl + N in edit mode will fix it)

    2. you got object inside other one and not hollow object.

    i modified your file so you can make difference correctly

    PS: watch out for thin walls (don't know your scale but 0,08 mm is not enough)
     

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    Last edited: Mar 19, 2013
  8. prismspecs
    prismspecs New Member
    Thanks!
    Okay one last thing before I print.

    I want to mount this thing on a CD player motor, which means I need a hole in the bottom that is a circle of 15mm. I can make that easy enough, the problem is that I want it to be centered on the shape by MASS, so that it doesn't spin out of control. How might I go about that?

    G
     
  9. Keymaker
    Keymaker Well-Known Member
    ctrl+alt+shift+C - origin to ceneter of mass
    and than move your cutter for hole accordinly
     
  10. prismspecs
    prismspecs New Member
    Awesome! Only problem is... can't seem to figure out how to move the cutter to that origin point. If I select it, the origin moves to the origin of the cutter.