Philip Thomas challenged us to do a Dodecahedron in less features. I did itin 4 features and 2 var.

tommie_berry

How do I contact Philip Thomas to meet his Dodecahedron challenge.
Is there a peer to peer message board , where I can call him out ?

emagdalenaC2i

You can mention @philip_thomas in a post, so he will be notify

lougallo

Click on his avatar in the forum to go to his profile page and then you can message him directly. 

emagdalenaC2i

@tommie_berry nice model

I try to improve it a bit:

• The angle between faces is constant so you don't need a variable for that
• I add the formulas to the length and angle relatives to the length of the edge: 
• Also change a bit the second sketch to remove fix constraints

So, now you can change the length of the edge and it works fine
https://cad.onshape.com/documents/f7b9f47a583fa0a31a4e212e/w/1bdf4751f06909ed3b66958c/e/39b198889376a4fb2553415c

Extrude depth = #Lado*sqrt((50+(22*sqrt(5)))/5)/2
Extrude draft = 90deg-acos(tan(18deg)*tan(54deg))

steve_shubin

tommie_berry said:

I am 71 today and I have no memory of this thread …

Funny how the memory isn’t as sharp as it used to be

Happy Birthday to a fellow old timer !!

glen_dewsbury

Happy birthday @tommie_berry from another old timer.

tommie_berry

Search the public parts for Dodecahedron to find mine.

emagdalenaC2i

tommie_berry said:

Search the public parts for Dodecahedron to find mine.

Please, share the link to the document instead wrote its name.

tommie_berry

Here is the link: https://cad.onshape.com/documents/25b86fbbfe89cc7c842a39ef/w/711421efeed1e7e69baca4bb/e/15d7a0c0c249e7094f51b522

emagdalenaC2i

You can mention @philip_thomas in a post, so he will be notify

lougallo

Click on his avatar in the forum to go to his profile page and then you can message him directly. 

emagdalenaC2i

@tommie_berry nice model

I try to improve it a bit:

• The angle between faces is constant so you don't need a variable for that
• I add the formulas to the length and angle relatives to the length of the edge: 
• Also change a bit the second sketch to remove fix constraints

So, now you can change the length of the edge and it works fine
https://cad.onshape.com/documents/f7b9f47a583fa0a31a4e212e/w/1bdf4751f06909ed3b66958c/e/39b198889376a4fb2553415c

Extrude depth = #Lado*sqrt((50+(22*sqrt(5)))/5)/2
Extrude draft = 90deg-acos(tan(18deg)*tan(54deg))

emagdalenaC2i

And... One more improvement 

One more feature to get a Dodecahedron as sheet metal part

philip_thomas

@tommie_berry - that will teach me to not look at the forums for a whole day!

It most definitely is an interesting problem! There was a whole thread a couple of years ago that @lougallo and others were all involved in. Here it is if you are interested in seeing the solutions of others;

https://forum.onshape.com/discussion/1419/does-anyone-have-a-dodecahedron-tutorial-or-can-comment-on-techniques-to-make-one/p1

In the end, John Sorrels (i dont know his forum name) won because he knew feature script was coming and did it in one feature

I searched the forums for 'dodecahedron' and had a good laugh when this came up!


I like your 'analytical' (variables and equations) solution.

Props also to @emagdalenaC2C for the first 'sheet metal dodecahedron'!

Also - gratuitous mention of @ilya_baran as he was another guilty party in the aforementioned thread.

Glad everyone is having fun!

ps - found it - @jon_sorrells

emagdalenaC2i

You can create now your own personalized dodecahedron pen holder 

philip_thomas

^^^^ NICE!!

robert_paynter531

I'm fairly new to OnShape and like it - I've got further up its learning curve than Fusion360, which I now suspect has a bit more to it, but as updates come through OnShape is catching up.
What about the "Five Cubes" polyhedron.

A construction that defines it is:
- Start with a cube extrusion of a square,
- Define axes which are the four diagonals between opposing corners.
- copy the cube and rotate 30° around each of those axes, thus creating four new cubes
that intersect and each main vertex is common between three cubes

The bit I can't work out is how to define the axes - it would be good if it was possible to define an axis as normal to a plane through a point or through two points.

I bet someone here would have pointers.

Toshimichi_Oda

https://cad.onshape.com/documents/24d784a9146cd7ff9cab76db/w/c85c59c01811aa6f32ff4180/e/e03dade6b06691475ba20339

I think it is better to use a sketche instead of calculator function.

EvanReese

@robert_paynter531
I was able to get it by referencing the equations on Wolfram here, I used my Freeform Spline feature to make the axis with a 2-point spline. Point one is on the origin and point 2 is (1, φ, 0). From there it's just a circular pattern at 72°. Here's my example studio.

tommie_berry

I am 71 today and I have no memory of this thread from 2017🤪 But I love the 4 feature solution.

steve_shubin

tommie_berry said:

I am 71 today and I have no memory of this thread …

Funny how the memory isn’t as sharp as it used to be

Happy Birthday to a fellow old timer !!

glen_dewsbury

Happy birthday @tommie_berry from another old timer.