Monday, July 23, 2007

missed some bonds and another tube


Looks like I missed changing some bonds when I made the tubes I used to make this junction. I have circled some of them in this picture. It's not that big of a deal; I pretty much just have to go back and click on them to change them to graphitic. Unfortunately I have not been able to find a way to change them all at once in alpha 8, maybe alpha 9.

I sometimes have serious trouble walking away from these things for the night, so...

Here is a very rough placement of another tube. Over the next two hours or so (not tonight though) I will work on adjusting the tube and junctions to the proper shape.

4 comments:

jim moore said...

Tom,
First, let me say I really appreciate the work you are doing. It is a lot of fun watching the work progress and seeing the successes and failures that happen is very educational. (I think I learn more from failures than the successes, so please don't stop posting when things don't work the way you planed.)

Back to the octet truss, I don't think that your basic unit will do the job. I just finished building a ball & stick model of an octet truss so let me try to explain in words what the repeating unit should look like.
From one central hub you have 12 struts going out.
In one horizontal plain you have 6 struts going out at 2 o'clock, 4 o'clock, 6 o'clock, 8 o'clock, 10 o'clock and 12 o'clock.
You have 3 struts going up out of the plain at 3 o'clock, 7 o'clock, and 11 o'clock.
And finally, you have 3 struts going down out the central plane at 1 o'clock, 5 o'clock and 9 o'clock.
All the struts are the same length and the angle between adjacent struts is 60 degrees.

Tom said...

so the structure at http://www.grunch.net/synergetics/octet.html or http://www.tabletoptelephone.com/~hopspage/Fuller.html
is not an octet truss?

Perhaps you should tell them too

jim moore said...

No, those are examples of sections of an octet truss. Its just that some of the stuts (at the edges) are not attached to a hub (because it is just a section).

Perhaps it would be usefull to think of an octet truss as one way to fill space, just like the cubic system you made earlier.

In that cubic system your repeating unit could be described as:
From one central hub you have 6 struts comeing out.
In one horizontal plain you have 4 struts coming out at 3 o'clock, 6, o'clock, 9 o'clock, and 12 o'clock.
You have 1 strut comming directly up out of the plain.
And finally you have 1 strut going directly down out of the plain.
All the stuts are the same length and there is a 90 degree angle between any two adjecent struts.

Tom said...

Okay, so I can still build those sections and connect them together to build a complete truss.

please send me a picture of your model if you can. I would also like to post it here too if that is all right.

Thanks for the help too!