Icosahedron 2

[QuicoPRC]

Hi,
I need to draw an icosahedron or a truncated icosahedron, anyone has an icosahedron template for solidfworks???

or how could I construct it?

 

[GoWithTheFlo]

Hum, I know that a couple of years ago I found a tutorial online on how to make Platonic solids... Some of them were really hard to do!

Just make a search on google, or you can import a model from another program.

 

[handleman]

I'd love to be able to show you how to do it, but my company has restricted access to any web hosting services. So here are some instructions:

1. Create a new part
2. Go to Tools->Equations and hit "New..."
3. Enter "Side = 1" (without quotes)
4. Hit "OK"
5. Hit "New..."
6. Type in (or copy/paste) the following line:

"Rad"= "Side"/2 *sqr(1+((1+sqr(5))/2)^2)

7. Hit "OK" and then "OK" again to exit the Equations dialog box
8. Create a new sketch on the top plane.
9. Draw an equilateral triangle centered on the origin. To do this, draw the triangle around the origin, then draw construction lines from each vertex to the origin. Make all three construction lines equal length, and make all three sketch lines for the triangle equal length.
10. Add a dimension to one side of the triangle. Right-click the dimension and choose "Link Value." Choose "Side" from the dropdown box.
11. Exit the sketch.
12. Create a new 3D sketch.
13. Draw a construction line normal to the top plane starting at the origin.
14. Draw a construction line from one triangle vertex to the end of the other construction line.
15. Add a dimension to the length of the second construction line and link that value to "Rad"
16. Exit the 3D sketch.
17. Select the two construction lines of the 3D sketch and to to Insert->Reference Geometry->Point. This will create a reference point at the intersection of the two construction lines of the 3D sketch.
18. Go to Insert->Boss/Base->Loft. For the Profiles, choose the 2D sketch and the Reference Geometry Point created in step 17. This will create an almost equilateral pyramidal tetrahedron. The base of the pyramid will have edges of length 1 and the other faces will have two edges of length 0.951057....
19. Choose one face of the pyramid and one of its 0.951... length edges. Create a circular pattern, 360 degrees, equal spacing, five instances. This will create a sort of flying saucer shaped body. Choose another 0.951... length edge and any face of the body and create another 360 degree, equal spaced, five instance pattern. The pattern will overlap itself in several places. This is OK. It will create an almost complete icosahedron.
20. Choose one more 0.951... edge and create one more 360 degree, five instance pattern. Your icosahedron is complete.

To change its size, change the equation "Side = 1" to whatever side length you want.

 

[rfus]

QuicoPRC,

I have one for you. Here it is:

http://www.box.net/shared/xnm922rl5x\

I made it the same way I made the 38 sided object in this post:
thread559-179431

Nobody came up with an answer. No mates or assemblies were used, and to prove it Here is a 56 sided object that will boggle your mind.

http://www.box.net/shared/910dr2mcp1

Can anyone figure it out?

RFUS

 

[EEnd]

So, I was intrigued by this and proceeded to create a 3D sketch of an icosahedron that I am satisfied with. I thought it would be easy to create surfaces by selecting edges in the 3D sketch to create triangular surfaces, but I could not find a command that worked like I expected. What I started doing was creating a plane, defined by three vertices, converting the edges in a sketch and then creating a planar surface. Needless to say I got bored of that well before I finished all 20 faces. I know I could use patterns in a manner to what handleman suggested. However, I was wondering if there was an easier way of creating the surface patches from the 3D sketch than the process of defining a plane, and then a sketch an then a planar surface. Any of you know of one?

Eric

 

[draftsman101]

That is so cool.

B. Long
P 4 2.80 GHz
2.5 Gig Ram
Solidworks Office 2007 Sp. 2.2

 

[MattBD]

I'd love to hear an answer to Eric's question. I'm starting with a "simple" tetrahedron, and I have no idea how to turn the 3D sketch into a solid or surface model. Is the method he describes the only way to create such a surface?

-Matt

 

[rfus]

Matt and Eric,

If you have a bunch of points or a single wireframe 3d sketch, the method of picking three points or vertices, creating a plane, generating a 2-d sketch on this plane, and then using a planar surface command on the sketch is one way to do it.

You cant do much for surfacing while in a 3d sketch, but outside of it, there are quite a few other ways to create planar surfaces such as:

You can loft an edge, 2d sketch line, or 3d sketch line to a point to create a planar surface. You could have a whole set of points in 1 3d sketch and start by creating one 3d sketch line. Loft this line to a point. You now have three other edges to loft to these points and so on and so on, so essentially you would only need one 3d sketch consisting of the tetrahedron points and one 3d sketch consisting of a line between the two points and you could keep using surface loft to create a closed surface network.

Using a surface fill on a closed 3d sketch with 3 edges or which is a polygon in a sketch plane creates a planar surface as well.

there are other ways to create planar surfaces with sweeps and rotations from 3d sketches.

These loft and fill methods will be a bit heavier on your feature stats than creating planes with 2d sketches, but they are quite useful and quick. Creating singular closed loop 3d sketches and use of the selection manager can be very useful when surfacing as well.

RFUS

 

[rfus]

Handleman, your icosaheron method was pretty awsome.

Here is the answer to how I created some of those buckyball like objects i put on here like my tetrahedron, 38 sided object and that 56 sided object.....

Imagine you are an electron. Now bound yourself to a sphere. Now bound your friend the electon to the same sphere. You will repel each other to the poles. Well, I replicated this algorithm for any number of electrons. If you looked at those solids all of there verticies are bound ot a unit vector sphere with the radius of one. If you put 12 electons on a sphere they will all repel each other equally and form the highest order platonic solid, known as the 20 sided icosahedron. There are some very interesting geometries that can be created. So, I was able to use the algorithm in a macro to create a 3d sketch point cloud, and then, with one 3d sketch line, the lofting to a point process I described above can begin. It really doesn't take long at all.

RFUS

 

[rfus]

Here is a pic to show the loft to point. Note that you can loft edge to edge as well with a connector(s)