Minimum Surface Presentation and Prof. Andrew Kudlass visit to our Class


Today, we introduced our second Grid Shell Model, produced entirely from our sessions on Grasshopper / Rhino, and made at the scale of ¾ inch = 1 foot,  with double the materials.

We also presented to the class our journey from Minimum Surface illustrated by our Soap Film models, and later by our Grid shell digital studies.

We quickly reviewed how the minimum structures began, and we reminded everyone that it began very humbly as:

  1. Circus tents
  2. Bedouin tents
  3. Tepee
  4. Yurt

However, nowadays, tensile structures have become ubiquitous:

Because membrane structures are everywhere:

  1. Munich Stadium
  2. Denver’s Airport
  3. Oaka Stadium in Athens
  4. The 1964 Olympic stadium in Japan

We made a direct comparison between tensile structures and soap.  They both look and behave alike because they are both minimal surfaces.  The soap film and the tent mold themselves to tension and compression. When the forces are in equilibrium – we have a stable and strong structure.  This situation is qualified with the word iconoclastic.

Soap and Tents are relatively light, easy to transport,  to fabricate, and to dismantle.

We also expressed how Frei Otto and Zhukov’s rotonda inspired us to make lots of soap model explorations.

We discussed the shape, characteristically, given to minimum surface structures:

  1. Hyperbolic
  2. Parabolic
  3. Square
  4. Circular
  5. Semicircular
  6. Hump tents
  7. Peak tents
  8. 4 point cross over tents
  9. Double curve

The soap film usually displays a 120-degree angle – indicating physically that the bubble is at equilibrium with its lateral, tension and compression forces.

We also showed our earlier group of models, and how we evolved through craftsmanship into a cleaner form.

Our New Shapes

  1. Curves
  2. Anchor diagonal lines
  3. Modified Squares

Early Model Making Materials

       1.  6 oz. jar of Glycerin
24 oz. of Walgreen’s Orange Liquid Dish Soap
66 oz.

2.  Walgreen’s Distilled Water

(As inspired by Frei Otto’s soap recipe.) (Nerdinger, page 19)

  1. Rubbermaid gallon container
Green plastic mixing bowl
Copper wire
1/16th of an inch wire roll (picture hanging wire).
  2. 18-gauge copper wire
1mm elastic cord (Bead Landing Brand)
1mm transparent elastic cord (Stretch Magic Brand).
  3. 18 w to 30 w soldering device
Soldering Wire
  4. A ruler
  5. Masking tape
  6. Scissors

Second List of Model Making Materials

For our first gallery exhibit, would need about four times the amount of soap:

  1. 24 oz. of Glycerin
  2.  96 oz. of  Walgreen’s Orange Liquid Dish Soap
  3. 264 oz. Walgreen’s Distilled Water
  4.  4 feet by 1-foot tank for our large model
  5. Copper wire
  6. 1/16th of an inch wire roll  (picture hanging wire)
  7. 18-gauge copper wire
  8. Plexi glass
  9. 1mm elastic cord (Bead Landing Brand)

10. 1mm transparent elastic cord (Stretch Magic Brand)

11. 18 w to 30 w soldering device

12.  Soldering Wire

13.  A ruler

14.  Masking tape

15.  Scissors Model Materials (a new revised list)

Later, we changed the recipe for soap, skipping glycerin altogether.  The glycerin had given us a spider web-like residue and we did not like it.   So, this time we only used soap.

17. 256 oz. of HEB Orange or Lemon Liquid Dish Soap  (it gave the water a nice pleasing color)

18. 7 gallons of Ozark’s Distilled Water

19. (Still inspired by Frei Otto’s soap recipe.) (Nerdinger, page 19)

20. 4 feet by 1-foot tank for our large model

21. 25 to 40 feet of 18-gauge Copper wire

22. 18 w to 30 w soldering device

23. Soldering Wire

24. A ruler

25. Masking tape

26. Scissors

27. 4 feet by 1 feet wooden box

28. Polyurethane

In this round, we built a soap tank; from wood – in it we were able to produce a soap substance of 7 gallons, deep enough for us to dip our entire 1-foot wide and 4 foot long model.

Our Last List of Materials

  1.  1/16-inch thick basswood
  2. 1/8 inch rivets
  3. A Stanley riveter gun
  4.  Masking tape
  5. Shears
  6.  Pliers

Tensile Structure normal Construction Materials

  1. Wood
  2. Cables
  3. Steel mesh
  4. Steel skin
  5. Steel masts
  6. Plastic skin
  7. Canvas
  8. PVC polyester fabric membrane materials.
  9. Ropes

10. Concrete anchors to tie the cables at the end at angle of 120 degrees from the horizon.

Our Changes to our Project Objectives

  1. Our initial objective:
    1. Was to successfully design a minimal transitional structure, with an iconoclastic membrane connecting the old Mc Nay to its new wing, providing an interesting path, for people to contemplate nature and transition from the classic collections to the new modern collection housed at the new wing.
  2. Later, we studied other geometrical forms:
    1. Such as the concept of murmuration – which means the basic flying geometry of a flock of birds.
    2. Continuous differentiation – the way algebraic equations get graphed can provide us with interesting forms.
  3. Our Third Objective:
    1. To concentrate on Grid shell made from wood.
    2. With some interesting cladding.
    3. Without buckling
    4. With lots of structural strength

Our last major soap film model had about 10 nodes linking parallelograms of every size at the beginning and some triangles.   It showed or configured a path.

The parallelograms helped support the structure as masts.

Further Exploration leads to Further Physical models and Digital Models:

On our last major soap film model, we focused on our model at a larger scale.   Our mode  had plenty of nodes.   These nodes were basically parallelograms.   Some of the parallelograms began at the same size.   Later, they gradually became smaller.   But, they were symmetrical.

The symmetry, on the model, made room for four individual entries:

  1.      1.  Two entries with a low catenary curve.
  2.      2.  Two entries with a high catenary curve giving the model some hierarchy, a datum line, and an axis.

We also showed a lot of repetition, and some transformation.

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.

Our New Exploration — The grid shell structure

These week’s structures were be made of:

  1. Plexi glass
  2. Basswood
  3.  Rivets

The Plexi glass did not work – So, we abandoned it, and we had a backup material such as jewelry bead wire, pre-cut basswood sticks and jewelry hooks.

Andres experimented with the bead wire and it was strong.  But, Aleks suggestion for the rivets worked best.

Our Exploration using Grasshopper, or Parametric Software


(to view our video — click on the file and let it download it on your computer — then double click on the image and watch it play on your computer)

We still like the four point Grid Shell because it seems more stable, gives us 4 points of entry, four anchors hold it, and it seems like a nice gathering place.

We looked and talked about a grid with only 3 anchors, but we did not like it as much.  We changed the supports by providing a double reinforced lattice wood.

We also researched on roof cladding, joinery, and anchors.   However, there is a chance it may buckle – so we need to tighten the top more, by bringing closer the anchor points, creating a catenary curve on top, or by strengthening the layers of the wood that support the ceiling.   We are also evaluating the skin pattern, and the join mechanisms.





Today, we visited the McNay and took pictures of the lot.   It is a sloped lot, with a drain; however, we still have the steps to the museum where we can configure a path for our structure.

We are also thinking about cost.



images copy 2

Everyone has learned a lot in these four weeks,  about soldering, about soap film, about carpentry, and especially Rhino, and Grasshopper.   Everyone in the group was able to practice with the tutorials.  We also learned we can speed up the process of moisture absorption of the wood if we add a little bit of ammonia.   Thanks to Ms. Pemberton for such a recommendation.













Aleks        Andres           Troy

 (Minimum Surface Group)

Edward Allen, Joseph Iano, Fundamentals of Building Construction: Materials and Methods (Hoboken, New Jersey: John Wiley and Sons Inc. 2004).

Francis D. K. Ching, Cassandra Adams, Building Construction Illustrated – Third Edition (New York: John Wiley and Sons Inc. 2001).


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