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Dean's Geodesic Dome and N-gon Pyramid Maker

by M_G May 25, 2012
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You're welcome and I look forward to seeing pictures!

I just started looking at printing a model made from your scad files but I'm having a problem when I change the number of triangles up to 10. When I change number of triangles from 9 to 10 in 2012_05_25-Deans_dome_pentagon_test-3.scad, the angle_tilt3, scaling_factor, and extra_height in the debug output become "nan" (Not A Number?). If I hit F6 to compile I see "Warning: Transformation matrix contains Not-a-Number and/or Infinity - removing object." I've tried it in OpenSCAD 2013-01 and 2014-03 and both fail.
Here's what I'm trying to accomplish... I have been making papercraft planet globes but they're too fragile to let kids hold so I was thinking of printing an n-gon to fit inside the paper to give them more structural strength. The paper templates I'm using are from a German site and they appear to be 120 sided for the smaller planets like Earth and Mars.
Source site: http://sternwarte-recklinghausen.de/interaktiv/bastelboegen/http://sternwarte-recklinghaus...
The planet models are under "Die Planeten" and are in PDF format.

Hello lowlight,
You get these errors when you try to generate a shape that self intersects (i.e. it flat would cover more than 360 degrees) or that cannot be folded up into a simple "pyramid" type shape. You will need to adjust the triangle_length_a, triangle_length_b or number_of_triangles values to make a valid shape (I would recommend reducing the triangle_length_a value until you get somethign generated).
Having looked at the file for Uranus and Earth on the website you linked it appears that these are not the same type of dome that my code is designed to make anyhow (as this code is based on using a mix of isosceles and equilateral triangles). Even so it SHOULD still be able to make something that works, but it may require some trial and error.
Looking closely at the files, they are not REALLY 120 sided objects, they are more like a 60 sided object. The whole planet is split into 12 groups composed of 5 shapes that are almost isosceles triangles, although one of these almost triangles is split in half and the bottom edges of each almost triangle has an additional shallow vertex. When roughly measured off my computer screen these almost triangles appear to be 50mm along the bottom edge and 84mm along the other two edges. Setting triangle_length_a=95, triangle_length_b=84 and number_of_triangles=5 will generate something that looks right.
IF you want to still generate a10 sided shape to actually make a 120 sided planet try setting triangle_length_a=50, triangle_length_b=84 and number_of_triangles=10, this seems to generate something that looks about right. Although I don't know how well it will fit together to make a 3d planet!
Good luck and be sure to upload a picture of a completed sphere if you manage to get it to work.

Thanks so much for giving such a detailed reply and not just ignoring me since you uploaded the model over 2 years ago. :) I'll definitely upload some pictures if I get it to work.