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The model
In this particular model all I did was to cut out equilateral triangles from thin hardboard .... (I did not bother with any angles)... then I glued the triangles to a piece of thin fabric and allowed it to dry.... I followed a 'net' from the web
Once dry I then folded it all together and tacked the joints with 'Duck Tape'
Then I glued along each joint.
Before assembling the 'finished ' product I will bandsaw along all edges that need to be cut at half the dihedral angles for say 1-2 I like to do all angles at one go.... so I need to colour code everything.
I love making these things.
I am enclosing a previous working model I used for the Truncated Icosahedron....
I actually measured all the angles on this model and then worked out averages.... I now know how to do this mathematically .... but I had a lot of fun doing it!
Soapy
Just a quick update on my project.
This is a quick hardboard model of the Icosahedron marked out for the 3V form.
Soapy
These figure 'feel' correct to me... thank ever so much!
I will try out the angles with some MDF ... possibly just a few rows of the 'Igloo' (base).
I have found, by experience, that very quicky one can soon judge if the figures are working out.
I must just say how much I have enjoyed this correspondence....
MATHS IS FUN
Soapy
Model No 2
Model No 1
In my post I wrote ...At this point the bases of 15 triangles make a plane
This is not absolutely correct.... in non mathematical terms... the base of the triangles .... are slightly 'crinke cut' so the top edge of the 'walls' each have a slight angle.
For anybody interested I am uploading two pictures of previous models.
Soapy
The image of the base... I hope
Thanks for information it is really appreciated.
Obviously, I will check this out on some MDF before I start to cut the angles on the Mahogany.
I will be revolving the 'sphere' on a smaller dome constructed in a very similar manner (constructed from a subdivided Icosahedron at a line just above half way where the triangles almost divide a plane)
At this point the bases of 15 triangles make a plane..... so I feel that is a sort of guide to the angles.
I am enclosing a picture of the shape and construction of the base that will house the motor drive .... just found a lovely motor.... quite powerful and with a bit of extra gearing I can get the speed down to 0.4 RPM
I saw the motor in a 'surplus' electrical goods shop .... £4.95 each.
Soapy Joe
Thanks Playing .... In my own 'tin pot' way I was comming to the same solution.
I had not fully figured it all out but do believe that I well on the way.
Thanks very much for your kind assistance.
I am at present working out a colour code for the components of each triangle .... cord B with 60.71 degree angles, cord B with 54.64 degree angles ..... etc.,etc.
Soapy
The triangles form 20 hexagons and 12 pentagons.
If you look at a football (Bucky Ball) which is of course a truncated Icosahedron... then decide to divide each face into roughly equilateral triangles ...we get 20X6+12X5 =180 triangles.
This is not how the 3V form of a Icosahedron is produced but this is the way that I first saw it .... I had made a model of a TI and looking at it thought .... if I now divide each face into smaller triangles I will get a better fitting model of a sphere.
Just checked.... I actually need 180 triangles for the 'sphere' and 90 or so for the base.
Soapy
Your help on this would be really appreciated.
I am no mathamatician... just very interested in the beauty of it all.
I have just started producing the square lenghts of Mahogany needed prior to constructing the 120 triangles required for the framework of the sphere and the 60 or so for the base.
I am quite happy about the chord data for the two types of triangles
Once these hollow triangles are constructed I then saw the various angles and start assembly .... I find powerful 'Bulldog' paper clips are a great asset.
When I constructed the Truncated Icosahedron model assembling it was pure poetry .... it went together with magical precision..... I must have got the angles 'spot on'.
It is going to take me several weeks to make the components for this model but it would be nice to know that I have the answer to the main problem that I face..... the ANGLES.
Yours
Squeaky
Thanks..... I suspected that all the figures needed are contained in the data that you posted.
It is just a question of fully understanding them .... that's up to me!
I am quite fascinated by this Pov-Ray Can you explain it a bit?
soapy
Yes, this is exactly the sort of thing that I mean.
What I want to know is at what angle do I set my bandsaw when cutting out the two forms of the triange?
I am uploading an image to see if it makes things a bit clearer.
Soapy
I am constructing a large model of the Three Frequency (3V) form of a Icosahedron.
Can anybody help me with the dihedral angles for the two triangles ?
Soapy
Thanks Ricky,
Making the full icosahedron is O.K. by the method you describe.... it is quite an ingenious method.... Thanks.
However, I want to make a truncated icosahedron which is made up of pentagons and hexagons.... I have read about it being described as a 'Buckyball'.
But thanks for replying.
soapy
I am very new to this forum so no rocket science please.
I am making wooden models of various shapes and need to be in a position to accurately work out the angles between the planes.
I have previously constructed hardboard models from 'nets' then roughly measured the angles .... now I would like to know a little more precisely the angles.
Soapy
Thanks Liuv,
Can you please tell me how you did this?
Soapy
I am building a wood model of a Icosahedron.
Can anybody tell me how I work out the angle that any two ajacent faces meet?
If you could direct me to formula for this sort of thing I would be happy to work it out for myself.
SoapyJoe