Parametric Coral Tubes, Concrete Wall Sculpture

Final. Framed and mounted above fireplace.
Closeup. This piece looks most interesting from sharp angles.
Underneath.

Build process: Modeling.

Modeled 3 different tube shapes using Grasshopper in Rhino3D.
This will be a wall hanging, so this is the head-on rendering.
An angle view.
Another angle view.

Build process: Silicone molds.

Positives printed on Formlabs SLA printer.
For each part, I 3d printed a casting sleeve and interior structural support.
Hot glue was used to seal the sleeve seam and attach the sleeve to a smooth surface — hot glue seals well and is easy to remove. The sleeve and model positive were coated lightly with Vaseline.
Since the models have some deep undercuts, I cast with a high grade silicone resin (Tap Plastics Platinum Silicone Resin). This is a soft and tear-resistant resin.

Build process: Concrete.

I reused the sleeves and insert to improve stability when casting concrete.
I used Buddy Rhodes counter top grade concrete mix with a generous amount of Owens Corning reinforcement fibers. I typically mixed concrete for 6 molds at one time, making the mixture wet enough to flow. After fully mixed, I moved the mixture to a large plastic Ziploc bag, cut one corner, and piped into molds.

Build process: Mounting and framing.

After pouring about 60 parts, I stained a 24″ x 24″ plywood board. I marked the layout grid with chalk, and attached each part with epoxy.
I made a roughly 5′ x 5′ “frame out of 5.5” walnut boards, using dowel joinery.
You can never have enough clamps.
Photo of back of joined main piece and frame. They are attached with 20 dowels (photo is from a test, some only a couple of dowels are inserted).

Boxen #1

Macro photo printed as a large format bitmap made up of 3d boxes in PLA Plastic, printed with Makerbot Replicator 2. Size: 6.5 feet X 2 feet.

Each “pixel” is a 3 dimensional box that tapers into a quadrilateral opening. The corners of the quadrilateral are determined by sampling the grayscale intensity of a grid of 9 subpixels within each box.

Example quadrilaterals, based on grayscale sampling

Inspired by “Bloom” from UC Berkeley.

Veronoi #3

Medium: PLA Plastic, printed on Makerbot Replicator 2 in 8 parts.

Modeled in Rhino3d with Grasshopper. Size of the veronoi part is 20″x20″. This was a super-challenging project to do with an FDM 3d printer, due to the large number of overhangs and small cavities. Each part took 10+ hours to print, but perhaps even more time to finish. I¬†used a large amount of support material that was, at first a friend, then… a nightmare to extract and sand down.

Prototype part, before geometry was smoothed, shows volume of support material.
Support material removed. Rough sanded.
8 parts, primed and medium-sanded.
Original model.

Some learnings:

  • If a space is too small to get your fingers into, it’s going to be a bear to sand. I took a few breaks from this project because finishing was so tedious.
  • This project likely would have been much easier with access to a dual head printer with water-soluble filament or an SLA or SLS printer. When I started this in 2013, I didn’t have any access to such equipment and printing something this size with an online service would have been cost-prohibitive.
  • Solvent glue works great with PLA.
  • Makerware’s generated support is pretty good, but I could have saved myself a lot of time by modeling my own support for precarious overhangs and certain bridges. I had to throw away some prints and patch some gaps when Makerware’s support failed.