Grove Branches

Dec 2017 - November 2018

"Mixed Media"

 

Baltic Birch Plywood, American Walnut Veneer, ABS Plastic Sheet, Plexiglass Sheet, Resin Castings, Aluminum Castings, Automotive Paint, Aluminum tubing, Laser-Cut Sheet Aluminum, DC Motors, Delrin Machined Parts, Assorted Hardware, Laser Cut Acrylic Sheet

This project was created for the Google Grove Experience Center in Redwood City, California. 

The centerpiece of the project is a 2-story tall assembly of programmable Redwood Trees. The trees were adorned with dozens of branches that are able to move up and down to simulate a breeze blowing through the space. I was tasked with designing, fabricating, and finishing the branches. In addition I designed parts of the enclosure that would house the electronics and motor assemblies. The Trees and the overall grove project and initial designs for all sub-assemblies were created by Zach Ali. The ceiling assemblies were designed primarily by Carl Bajandas with some of the procedural generation being assisted by Greg King

 

Essential to this project is the movement of the branches, this is an early prototype that shows the movement we were hoping to achieve. Making a scale prototype allowed us to test the strain on the motor and the necessary amount of counterweight needed to ease the load on the electronic parts. 

The tree segments were first fabricated in their entirety inside of our Pittsburgh studio before being taken down for veneering and finish work, and shipped in their unassembled state to their final destination. 

Early digital prototyping allowed us to get a sense of assembly and aesthetics without needing to take time and materials to create physical prototypes. 

One early change that was made was to alter the steel counterweights on the rear of the branches. This component, designed to reduce strain on the motors, the assembly could weight as much as 40 pounds. When installed these parts would be hanging 11 - 26 feet in the air directly above the viewer heads. We needed to make sure they were securely fastened at all times. Part of that process was making them a loop rather then a horseshoe shape as seen on the right. 

Final designs were realized in CAD, wooden prototypes were fabricated and test fit together. Since a number of these parts could not be fabricated in house we then started to get quotes from a number of local suppliers and contractors to have the metal work produced.

The parts that would take the longest and wind up being the biggest headache were the 3/4 Steel and Aluminum counterweights. Here are the proofs waterjet from 3/4" aluminum which fit together flawlessly. We would later encounter tolerance issues 

The "Foliage Supports" act as the rigid aluminum spine for the printed acrylic "Leaf Panels". It was laser cut from 3000 series aluminum and bent on a metal brake. 100 of these parts were made, mirror images of each other ‚Äč50 left, 50 right. This part also gave some fine adjustability to the counter-balance of the branch as it could be adjusted fore or aft once installed in the tree with the leaf panels attached. 

Once the metal parts had been commissioned by local fabricators we got to work machining the branch "Limbs" from 1/2" Puma-Plywood. All substrate for this project needed to by fire retardant to match building standards. 

Some parts were veneered in house other we hired additional help, this job was too big to be handled by our small team alone.

Due to UL restrictions on electronics being installed into this project and the aesthetic preferences of the client it became necessary to redesign the system for holding our motor/controller assembly on each branch. 


Here was the mockup of the system that we eventually implemented.

Each 'column' of every tree was secured to those next to it by steel lateral braces which also served as the mounting point for the branch. Installation of these parts proved to be more difficult then originally anticipated and the decision was made to cover them rather then try and apply finish directly to the steel. These 'plates' would encircle the brace and hold the motor for each branch where necessary.

This is an example of the 'Motor Plate' assembly and how it would be installed. One important goal for this sub assembly was to encompass the steel brace without modifying it. Installing the plate around the existing brace would allow it to retain it's full strength as approved by the engineering firm overseeing this project. 

Prototypes for this part were made from rigid high-density architectural foam but the final pieces were fabricated from solid ABS plastic. This was a material we could easily fabricate in house and could be more easily finished with the approved automotive paint. We also created paint tests in acetal delrin and PVC. 

Cutting the required ~80 plates for this part of the project took close to 30 hours of continuous milling time. Plates were fabricated in small, medium and large sizes to correspond to the tree they would be installed into.

The tops of each plate were made from laser cut 1/8" and 1/4" acrylic which was deemed to be strong enough to support the motor assemblies and the stresses of the branch riding on the CAM. It also allowed us to parallelize the fabrication of the top of the plate and the bottoms as well as being cheap and easy to replace if one was damaged. 

All of the branch limbs were finished with a sealer coat and 3 coats of polyurethane on the veneer. Polyurethane was applied with an HVLP Gun allowing this process to be greatly sped up. Between each coat they were sanded with high grit sandpaper and the dust was removed with mineral spirits and tack cloths. 

Close to 100 branch limbs were produced, having all the parts for this project be modular really saved us from having issues with shipping or damage from installation and handling. 

One final branch assembly was created on site in Pittsburgh to confirm the fit and finish of all the pieces. 6 different profiles of plastic leaves were created each needing different extensions of the 'foliage supports' and different configurations of aluminum and steel counterweights to ensure a light touch on the cam. 

Once on site the configuration of each branch was decided by the overall grove project lead. Larger leaves would be up top and smaller leaves closer to the viewer on the ground. Branches were assembled and the counterweight adjustment was tested. Branch installation was the last component to go into the trees and needed to be installed concurrently with two access panels that helped with servicing the electronics of the trees. 

 

While not delicate a lot of care needed to be taken while assembling these parts because the facility was still an active construction zone for much of our installation period. 

 

Ethan Gladding