Punica: folding Miura-ori with divots

Figure
Punica, 2019. 22″ W by 22″ D by 26″ Hi-tec Kozo paper, stainless steel

Free access at https://www.tandfonline.com/toc/tmaa20/current till the end of 2020.

Citation: Wu, J. (2020). Punica: Folding Miura-ori with divots, Journal of Mathematics and the Arts, Volume 14, Issue 1-2, pp. 170-172. doi: https://doi.org/10.1080/17513472.2020.1733914

The transformation of a flat sheet of paper to a three-dimensional form through folding is easy and yet complex. Conceptually, folding is always in-between, bringing together two edges and the inside and outside. As a material operation, folding is always unstable. A fold stores kinetic energy, which allows the folded form to contract and unfurl. I am fascinated by folding as a tactile process of working with material – for instance, paper, or other rigid sheet materials. I am drawn to these naturally occurring folds and working on understanding how they can be analysed in order to understand the material tectonics. I use balancing, connecting, hinging, suspending, pulling and popping in my works. I often fold intuitively and tactually using small pieces of paper first, oscillating between states of disequilibrium and equilibrium.

Unfolding a folded design reveals a patterned map of creating and generating. And this map, also called a ‘crease pattern’, is often the result of counterintuitive deliberation and calculation based on mathematical understanding. While it is difficult to describe the folded form through the visual characteristics of the folds on this map, it is even more difficult to reverse engineer and come up with logical patterns of folds that can then be folded into desirable forms – in other words, even though one can think of or see what one wants to fold, it is still very difficult to come up with a crease pattern. I often explore mathematical understanding and computational algorithms in generating a map of folds. These final outcomes of patterns of folds are often etched and cut on very large sheets of paper using an industrial-scale laser cutter. These large sheets of paper, sometimes as wide as 5′ and as long as 10′, are then hand creased and folded in my studio.

A simple fold has many possibilities and can generate many visual results, and it can be discovered only by folding. Only through the act of folding that is grounded in material reality, one can find out what the folds want or need to become visually. To bring folds and folding together, I alternate between intuition and calculation, imagination and logic. An accidental crimp or crinkle in the small pieces of paper may reveal an internal logic to organizing and abstracting the fold. When all the folds are organized and folded in a large sheet of paper, the folding in the material may behave in a self-organized way. When this happens, I stop folding. I observe how the material self-folds and self-assembles.

Punica is the Latin name for pomegranate. I named the work shown below Punica as it reminded me of the silhouette of the pomegranate flowers that I saw while growing up in Southeast China. Punica is folded based on flat-foldable Miura-ori tessellation with divots. Miura-ori tessellation, credited to Japanese astrophysicist Koryo Miura, has become well-known for its application in deployable structures, such as the solar array deployed in a 1995 mission for JAXA, the Japanese space agency (Miura, 2009). It is made of repeated parallelograms arranged in a zigzag formation and has only one type of vertices: a 4-degree of vertex. A key feature of the Miura-ori is its ability to fold and unfold rigidly with a single degree of freedom with no deformation of its parallelogram facets. Robert Lang, who wrote several books on origami and mathematics, described a method to semi-generalize the Miura-ori in order to generate any arbitrary target profile for surface with rotational symmetry without almost no mathematics involved (Lang, 2018).

In general, to fold Miura-ori into smooth curvature is materially impossible – the width of paper corrugation will be too small to fold physically. So, in order to generate folded surfaces with smooth and gentle curves, Miura-ori is altered by adding divots. Using linear algebra, I work with algorithm-based design tools such as Grasshopper and Rhino in order to study parametric changes of the folding angles and their relationships to the target smooth curved profiles. In the work shown here, an approximation of the target profile of a sine curve is generated first. And this profile curve is then arrayed and stretched into a rotational double-curved surface with both a positive Gaussian curvature value and a negative Gaussian curvature value.

For the full article, please go to https://www.tandfonline.com/toc/tmaa20/current

Figure
Punica, 2019. Top figure shows the sine wave profile when Punica is flat folded, while the bottom figure shows the layered effect with the light.

Weaving Infinite Bi-foldable Polyhedral Complexes

I have been collaborating with mathematician Matthias Weber on a new class of infinite bi-foldable polyhedral complexes. Currently, our initial result has been published at: https://arxiv.org/abs/1809.01698. I would like to showcase two examples of triply infinite bi-foldable polyhedral complexes: Butterfly and Dos Equis. I made Butterfly and Dos Equis using a polyhedral weaving technique. The material is Mi Teintes paper. I’m also including two nice rendered videos made by Weber.

To learn more about the mathematics (explained in layman’s terms by Weber) behind these fun infinite bi-foldable polyhedral complexes, or the process of how we found them, I encourage you to visit Weber’s blogs here:

Weber’s blog on Butterfly
Weber’s blog on Dos Equis

An frontal view of Butterfly

Butterfly has three vertex types: valency 4, 6, and 8. Butterfly is named after the vertex of valency 8 as it resembles a symmetrically balanced butterfly. This vertex is translated to create the triply periodic construction. Butterfly is made using a polyhedral weaving technique that employs a four-color complementary scheme. Each color represents a distinctive zone using the concept of zonohedron proposed by H.S.M. Coxeter. Each face is alternated and interwoven by two zones of two colors. A few deviations from the regularity are inserted to create the rhythmic changes.

An isometric view of Butterfly

There are three vertex types in Dos Equis: two of valency 4 and one of valency 8. Dos Equis is named after the vertex of valency 8 as it resembles the image of an X. Using a four-color complementary scheme, each color represents a distinctive zone using the concept of zonohedron proposed by H.S.M. Coxeter. Each zone, using two unique unit patterns, is then folded and interwoven with other zones. Notice that the four colored zones, with its two unit patterns, and its under or over weaving alternations, create a total of sixteen design variations for the quadrilateral faces.

Dos Equis


Applying Helical Triangle Tessellations in Folded Light Art

Citation: Wu, J. (2017). Applying Helical Triangle Tessellation in Folded Light Art. In D. Swart, C Séquin. & K. Fenyvesi (Eds.), Proceedings of Bridges 2017: Mathematical Connections in Art, Music, and Science (pp. 383-386), Phoenix, Arizona: Tessellation Publishing

Link to full paper in PDF

Abstract: This article describes how I created a collection of lamps made of folded sheets of material using helical triangle tessellations, which are also called Nojima patterns. I started by working with a periodic helical triangle pattern to fold a piece of light art that is shaped in a hexagonal column. I continued by modifying the periodic pattern into a semi-periodic design by adding variations so that the tessellation could be folded into a light art that is shaped in a twisted column. I further developed tessellations that consisted of self-similar helical triangles by using a geometric construction method. These self-similar helical triangles form algorithmic spirals. I folded the tessellation design into a work of light art that is shaped in a conical hexagonal form.

2017 Mathemacal Art Exhibition Awards

light_torus_night_1.jpgThe 2017 Mathematical Art Exhibition Awards were made at the Joint Mathematics Meetings last week “for aesthetically pleasing works that combine mathematics and art.” The three chosen works were selected from the exhibition of juried works in various media by 73 mathematicians and artists from around the world.

“Torus,” one of my folded light art, was awarded Best textile, sculpture, or other medium. I’m interested in how paper folding can be expressed mathematically, physically, and aesthetically. Torus is folded from one single sheet of uncut paper. Gauss’s Theorema Egregium states that the Gaussian curvature of a surface doesn’t change if one bends the surface without stretching it. Therefore, the isometric embedding from a flat square or rectangle to a torus is impossible. The famous Hévéa Torus is the first computerized visualization of Nash Problem: isometric embedding of a flat square to a torus of C1 continuity without cutting and stretching. Interestingly, the solution presented in Hévéa Torus uses the fractal hierarchy of corrugations that are similar to pleats in fabric and folds in origami. In my Torus, isometric embedding of a flat rectangle to a torus of C0 continuity is obtained by using periodic waterbomb tessellation.

The work is made of Hi-tec Kozo Paper and measures 45 x 45 x 20 cm.