Rocky Tensegrity Table

Lesson Plan and Activity:

With a partner, design and create a single custom Tensegrity Structure of equal complexity or greater as the tables depicted above.

Parts List:

2 connector pieces, 1 bottom base piece, 1 top base piece

10 small screw hooks

About 192 cm of fishing line(recommended to use slightly more to account for excess)

Assembly/Construction Instructions Section:

Check to see if all marked screw holes printed properly

1. If needed(ie; screw holes are too small), align Phillip’s head screwdriver or awl with screw holes(1 on each connector, 4 on each base)
   
    
2. Lightly hammer on the end of the screwdriver or awl to widen the hole and allow the screw hooks to “bite” in(hold the piece down with a vice or have someone else hold it down)
3. Grap screw hook using pliers, align it with a screw hole and turn it in, applying pressure, until screw is fully in and not moving
4. Repeat previous steps for all screw holes
5. Pick ONE connector and cut off the end of the hook that is attached to it
6. Attach the connectors together using the hooks
7. Slot connectors into corresponding slots on bases
8. Cut string or fishing line into 4 equal pieces
9.  Connect corresponding hooks on bases using string or fishing line and tighten
10. Tie the excess string in another knot after finishing tightening all the strings
11. Cut off excess string and adjust the string so the knot is on one of the hooks

Design Choices

The first major change we made was switching from the spline tool to the freeform tool. Originally, we were going to use the spline tool on the sides and surfaces of both bases. This would give our bases the terrain look we were going for.

We also used the spline tool, along with other tools, to make different shapes to go on each base.

However, we struggled to keep our designs from looking uniform, as it can be hard to make unique shapes with the spline tool that can print well. We decided to switch to the freeform tool, which allows you to add curves and bends to straight lines. This gave us a lot more freedom with how we could design our bases. After this was done, we took all of our parts and put them together in an assembly. While we were going to print each part individually, this helped us see how everything looked together before we printed.

 Once this was done, the next big change was adding shapes to all four corners of each base, rather than just two corners. This change allowed the bases to look more complete, but also gave us the opportunity to add more creativity to the structure, as in total we now had eight different shapes across the two bases.

Next, we made very similar changes to our two connectors. We started by also switching these from spline to freeform. This helped them curve more in order to make them less uniform. Next, we each used the freeform tool to design our own connectors rather than having the same connector twice, once again helping to make everything look more unique.

We then took all these new parts to create our updated assembly.

We liked the way our assemblies looked, so we were now ready to add models of screws and hooks into our assemblies. However, we then realized that it would be difficult to insert them into the printed parts with our current design, so we added pegs onto each shape in order to make this more feasible.

We were then able to successfully add in the screws and hooks, and we deemed our assembly ready to print.

While assembling version 1.0 went very well, one huge issue was that everything came out very small. For the bases, we scaled everything up by 2x on the x-axis and z-axis, but not the y-axis, as we wanted to maintain the same thickness for each base.

Then, in order to make sure the connectors could still fit, we scaled the entirety of the connectors up by 2x as well. However, we decided to go back to our original plan of using the same connector twice rather than two different connectors, as having two would make the process of trying to connect them to the bases rather difficult. With this connector, we decided to make the top very flat and add a hole for the hooks to go into, as trying to insert the hooks into the version 1.0 connectors proved very difficult.

Lastly, to help make attaching the connectors and bases easier, we extended the pegs on the connector and the holes on the bases to be twice as long.

With all these changes out of the way, we were ready to re-print everything, and we constructed our final assemblies.