Minimal Surface and Grid Shell Structures
Written by ysk251
4th Minimal Surface Blog Entry
Our Grasshopper Based Grid Shell Physical Model Exploration and
Our Grasshopper Digital Model Exploration…
Our Grasshopper-based Grid Shell Physical Model
Plexi glas strips
This week, we began to plan our Grid Shell physical model. We initially wanted to make it of Plexiglas because it would simulate material that is both structural and membrane-like.
But, after we sent it to the laser cutter – it did not cut well and it produced fumes. Instead of cutting it, it simply scored it.
We tried to cut it with scissors, or with a blade, but it proved to be too difficult to cut. Afterwards, Andres found easier to individually pull the strips, one strip at a time and it cut better. But, at times it tore and entire row of strips causing us more problems and ruining the pieces, much to my teammates chagrin. After much thought, we grew tired of its instability and decided to abandon it permanently. Besides, Mr. Mc lellan had previously indicated he did not think it would work.
So, after much thought, we decided to make it with 1/16-inch wood, which was rigid and once moist becomes pliable. It was cut into ¼ inch wide strips of 24-inch length. The laser cutter also cut some holes into the wood to make easy to add the joining mechanical pieces.
We kept researching for more materials. We thought about fasteners. But, the companies that distribute screws, washers and bolts mostly close early and only operate during on weekdays when we have to attend classes.
Aleks had a very good idea; he decided to purchase 1/8 inch thick rivets and a Stanley riveter gun.
Andres purchased already cut 1/16-inch basswood sticks in case we needed it for a second model, jewelry bead wire, and bead hooks – with the idea of interlacing the wood sticks creating a grid shell structure by hand.
However, Aleks’ initiative worked better. After trimming the strips at the laser cutter on Sunday, he moistened each strip, and molded the form modeled digitally by the Grasshopper parametric software.
Below, we have a plan view, and some elevations.
One of the elevations shows a narrow opening while another picture shows a very high and still narrow opening.
The narrow opening seems more feasible to build for it had had more support.
1. This is the digital model we chose, and from which we based our last model.
- This is our second attempt looked the same, except some of the lines across had been spaced at a wider width, similarly to the picture of Grid shell Napoli from Italy.
Basic Grid Shell Shape plan.
Basic Grid Shell Perspective
- The third attempt was to incorporate to make a curved grid shell with only four anchors, and wider spacing between the lines across.
Basic Grid shell plan with a curved anchor.
- This fourth attempt had even a wider spacing between the lines across.
Basic Grid shell – wide intersections. Plan view.
Basic Grid shell with wide intersections. Perspective.
- This iteration showed an interesting aesthetically pleasing pattern, which would be also structural.
- Basic Grid shell – wide intersections. Plan view.
- This example shows four anchors, one of the anchors had an inward curve.
- The first model was had a more basic grid shell shape like the one pictured below from Grid shell Italy.
Basic Grid Shell Shape plan.
Basic Grid Shell Perspective
- This is another example of a basic grid shell structure that we explored, but was not selected.
Basic Grid shell plan with a curved anchor.
Last week we spent considerable time working on Grasshoppers. Unfortunately everyone had some issue with the installation of Rhino and Grasshopper. Particularly issues with a periodical license audit that somehow had a conflict with the school’s Wi-Fi or its firewall.
Aleks and Troy had it installed on their Windows laptops, and Andres got his Mac working with a new license for Parallel 9, Windows 8.1 64 bit, and Rhino 5 for Windows. We are all excited practicing with Grasshoppers, redoing the tutorials and learning at their own pace.
We also presented our article about Frei Otto (An interview with Frei Otto) and its minimal surface structures today in class.
Today, the craftsmanship of our model won some nice critiques from our professor and encouraged everyone to try to use fasteners such as the ones we displayed.
Andres also brought a sample from the hardware store, an MDF board, that he will soon be returning for it is not strong enough for our project.
We discussed possible buying Douglas fir wood; pine, maybe even bamboo, and we also discussed fasteners, screws, bolts, and washers.
We also reviewed some of the sources of our inspiration such as Arturo Tedeschi, and Grid Shell Italy.
It was stimulating to watch the presentations from the other students particularly the one on Morphogenesis, the transformation of materials in order to produce new materials for new architectural styles, and my favorite of all – the catenary curves with correlates well with our minimum surface research.
Characteristics of our Model
It was light, safe, and economical but we can’t assemble it or dismantled easily yet. We need to make another iteration in which we build it flat and then it folds out and becomes a grid shell. But, it will provide the volume shape we need for our project at the McNay museum.
Our minimal structure is still be respectful to nature and for it has no slab. So, neither trees nor landscaping shall be affected.
The appearance of our model still conforms to forms of nature, resembling a mountain, a valley, a jellyfish, a cell under a microscope, or a flock of birds. We are still true to Frei Otto.
Our Old Type vs. Our New Type
Last week, we experimented with a simple tent that simulated some of Frei Otto’s experiment. In fact, it looked like hump tent.
Today, we worked exclusively with the Grid Shell, as discussed on our Grasshopper classes.
This week’s Minimum Surface construction has these shapes:
- A basic curve with two anchor points.
- A basic curve with three anchor points.
- A basic curve with four anchor points.
- 2 or 3 variations of the first three above by changing the size or the shape of the Single curve.
Materials (A revised list)
These week’s structures were be made of:
- Plexiglas
- Basswood
- Rivets
The Plexiglas did not work – So, we abandoned it, and we had a backup material such as jewelry bed wire, pre-cut basswood sticks and jewelry hooks.
Definitions for this week
Parametric software – a software that helps designers make models our physics and mathematics utilizing rhino efficiently with less memory than other simulation models in the market.
This software is of course Grasshopper.
Description
The shapes of the minimal structures we mostly experimented were:
- Curvilinear
- Curve,
- Sort of a transformed Square,
Objective (Revised)
Our objective is still to design a minimal transitional structure, but in this iteration our focus was on making it based on Grid shells.
We will maintain the connection with nature through its gardens because the structure will be made from a clear roof or covered with a membrane
We reduced our shapes to the following geometric shapes:
- Curves
- Anchor diagonal lines
- Modified Squares
Hypothesis
A Minimum structure can be built using tension and compression, tensile material or fabric, and anchor support. Except that now we added wood. We did simulate our model by increasing our scale to an object that is about 30 inches feet long and 30 inch wide. Now, we have to continue experimenting with our digital model and figure out how would it look at a larger scale.
Model Materials (a new revised list)
No soap recipe this week. It
1/16-inch thick basswood
1/8 inch rivets
A Stanley riveter gun
Masking tape
Shears
Pliers
Our Experiment:
This week we focused on our model at a larger scale. Our model plenty of nodes. These nodes were basically parallelograms. Some of the parallelograms were basically the same size. They were symmetrical.
The symmetry, on the model, made room for four individual entries:
- Two with a low catenary curve.
- Two with a high catenary curve giving the model some hierarchy, a datum line, and an axis. We also show a lot of repetition, but not much transformation this time.
Since we have four entries – this would translate into a four-path configuration. You can enter from either end and walk underneath this structure. Its shape provides enough volume to visually guide people in one or 4 directions making it a perfect gathering place.
Yet, we are still at a very conceptual stage although feasible.
The model supported itself well.
Andres Mulet Aleksandr Mikhailov Troy O’Connor
(The Minimal Surfaces Group).
Bibliography
CMMKM Architecture and Design – “Pavilion built for Naples School of Architecture courtyard, University of Naples “Federico II” (2012) < http://www.gridshell.it/gridshell_selinunte>
Tedeschi, Arturo, “GRIDSHELL | form finding experiment with Kangaroo, A T Architecture and Occupational Design – December 2012” < http://www.arturotedeschi.com/wordpress/?page_id=5467> (accessed Feb. 10, 2014).
