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# Math Question

paul_bartlett
Member Posts:

**69**✭✭
in General

I am trying to create a sphere using 60 triangles each extruded 1 inch and the bottom surface is beveled at 8.95 deg and the 2 side surface are beveled at 13.22 degrees. when I assemble 5 of them which gives me a pentagon shape the last one over laps the first on by a small amount meaning I do not have the 13.22 angle quite right. Would anyone know how to figure out the correct angle? 12 of these pentagons would create the sphere I am trying to get.

https://cad.onshape.com/documents/2a58d84a32fa24a92fe052f7/w/915d6437d094bcab63b4b12f/e/5a10fa294451dfc5847b9ec6

https://cad.onshape.com/documents/2a58d84a32fa24a92fe052f7/w/915d6437d094bcab63b4b12f/e/5a10fa294451dfc5847b9ec6

0

## Comments

69✭✭https://cad.onshape.com/documents/2a58d84a32fa24a92fe052f7/w/915d6437d094bcab63b4b12f/e/5a10fa294451dfc5847b9ec6

2,812PROCheck out this guy's walk through for an Icosahedron

https://www.youtube.com/watch?v=AZJMIVVUHiI

69✭✭https://cad.onshape.com/documents/2a58d84a32fa24a92fe052f7/w/915d6437d094bcab63b4b12f/e/5a10fa294451dfc5847b9ec6

2,812PROCAD can be picky and cause mate errors, or faces being out of alignment if it is even slightly off. In these cases where irrational or high decimal precision numbers are used, it is usually better to build off geometry and take advantage of boolean operations to cut the faces and angles in 3D space.

But it sounds like you may be describing a "pentakis-dodecahedron" according to This Site

I'm not a mathematician so I don't know for sure

But it looks like there is enough information to describe your shape with math on that site.

4769✭✭This is exactly what I am trying to create in Onshape The 60 triangles are not equilateral the base is a different length than the 2 sides. Still no clue as how to create this because of the non-equilateral triangles. I can definitely do it if the triangle sides are all the same. Sorry to keep hounding on this. I just cant seem to let it go. But maybe I'll have to.

3,130https://cad.onshape.com/documents/3a40059de1a0758ff8e1527e/w/fbec920598b1f8a352f30418/e/eb9b7e0dabb852fa03571647

2,812PRO69✭✭https://cad.onshape.com/documents/3a40059de1a0758ff8e1527e/w/fbec920598b1f8a352f30418/e/eb9b7e0dabb852fa03571647

3,13069✭✭3,13069✭✭