37°
Tag: 3D printing
Developing Space-Filling Fractals
Delving deeper into the world of mathematics, fractals, geometry, and space-filling curves.
Foreword
Following my last post on the “…first, second, and third dimensions, and why fractals don’t belong to any of them…“, this post is about documenting my journey as I delve deeper into the subject of fractals, mathematics, and geometry.
The study of fractals is an intensely vast topic. So much so that I’m convinced you could easily spend several lifetimes studying them. That being said, I chose to focus specifically on single-curve geometry. But, keep in mind that I’m only really scratching the surface of what there is to explore.
4.0 Classic Space-Filling
Inspired by Georg Cantor’s research on infinity near the end of the 19th century, mathematicians were interested in finding a mapping of a one-dimensional line into two-dimensional space – a curve that will pass through through every single point in a given space.
Jeffrey Ventrella writes that “a space-filling curve can be described as a continuous mapping from a lower-dimensional space into a higher-dimensional space.” In other words, an initial one-dimensional curve is developed to increase its length and curvature – the amount of space in occupies in two dimensions. And in the mathematical world, where a curve technically has no thickness and space is infinitely vast, this can be done indefinitely.
4.1 Early Examples
In 1890, Giuseppe Peano discovered the first of what would be called space-filing curves:
An initial ‘curve’ is drawn, then each element of the curve is replace by the whole thing. Here it is done four times, and it’s easy to imagine how you can keep doing this over and over again. One would think that if you kept doing this indefinitely, this one-dimensional curve would eventually fill all of two-dimensional space and become a surface. However it can’t, since it technically has no thickness. So it will be as close as you can get to a surface, without actually being a surface (I think.. I’m not that sure..)
A year later, David Hilbert followed with his slightly simpler space-filing curve:
In 1904, Helge von Koch describes a single complex continuous curve, generated with rudimentary geometry.
Around 1967, NASA physicists John Heighway, Bruce Banks, and William Harter discovered what is now commonly known as the Dragon Curve.
4.2 Later Examples
You may have noticed that some of these curves are better at filling space than others, and this is related to their dimensional measure. They fall under the category of fractals because they’re neither one-dimensional, nor two-dimensional, but sit somewhere in between. For these examples, their dimension is often defined by exactly how much space they fill when iterated infinitely.
While these are some of the earliest space-filling curves to be discovered, they are just a handful of the likely endless different variations that are possible. Jeffrey Ventrella spent over twenty-five years exploring fractal curves, and has illustrated over 200 hundred of them in his book ‘Brain-Filling Curves, A Fractal Bestiary.’ They are organised according to a taxonomy of fractal curve families, and are shown with a unique genetic code.
Incidentally, in an attempt to recreate one of the fractals I found in Jeffery Ventrella’s book, I accidentally created a slightly different fractal. As far as I’m concerned, I’ve created a new fractal and am unofficially naming it ‘Nicolino’s Quatrefoil.’ The following was created in Rhino and Grasshopper, in conjunction Anemone.
You can find beautifully animated space-filling curves here:
(along with some other great videos by ‘3Blue1Brown’ discussing the nature of space-filling curves, fractals, infinite math, and more)
On A Strange Note:
It’s possible to iterate a version of the Hilbert Curve that (once repeated infinity) can fill three-dimensional space.
As an object, it seems perplexingly difficult to categorize. It is a single, one-dimensional, curve that is ‘bent’ in space following simple, repeating rules. Following the same logic as the original Hilbert Curve, we know that this can be done indefinitely, but this time it is transforming into a volume instead of a surface. (Ignoring the fact that it is represented with a thickness) It is a one-dimensional curve transforming into a three-dimensional volume, but is never a two-dimensional surface? As you keep iterating it, its dimension gradually increases from 1 to eventually 3, but will never, ever, ever be 2??
Nevertheless this does actually support a statement I made in my last post suggesting “…there is no ‘first’ or ‘second’ dimension. It’s a bit like pouring three cups of water into a vase and asking someone which cup is the first one. The question doesn’t even make sense…“
5.0 Avant-Garde Space-Filling
In the case of the original space-filling curve, the goal was to fill all of infinite space. However the fundamental behaviour of these curves change quite drastically when we start to play with the rules used to generate them. For starters, they do not have to be so mathematically tidy, or geometrically pure. The following curves can be subdivided infinitely, making them true space-filling curves. But, what makes them special is the ability to control the space-filling process, whereas the original space-filling curves offer little to no artistic license.
5.1 The Traveling Salesman Problem
Let’s say that we change the criteria, from passing through every single point in space, to passing only through the ones we choose. This now becomes a well documented computational problem that has immediate ‘real world’ applications.
Our figurative traveling salesman wishes to travel the country selling his goods in as many cities as he can. In order to maximize his net profit, he must make his journey as short as possible, while of course still visiting every city on his list. His best possible route becomes exponentially more challenging to work out, as even just a handful of cities can generate thousands of permutations.
There are a variety of different strategies to tackle this problem, a few of which are described here:
The result is ultimately a single curve, filling a space in a uniquely controlled fashion. This method can be used to create single-lined drawings based on points extracted from Voronoi diagrams, a topic explored by Arjan Westerdiep:
5.2 Differential Growth
If we let physics (rather than math) dictate the growth of the curve, the result becomes more organic and less controlled.
In this example Rhino is used with Grasshopper and Kangaroo 2. A curve is drawn on a plain, broken into segments, then gradually increased in length. As long as the curve is not allowed to cross itself (which is achieved here with ‘Collision Spheres’), the result is a curve that is pretty good at uniformly filling space.
The geometry doesn’t even have to be bound by a planar surface; It can be done on any two-dimensional surface (or in three-dimensions (even higher spacial dimensions I guess..)).
Additionally, Anemone can be used in conjunction with Kangaroo 2 to continuously subdivide the curve as it grows. The result is much smoother, as well as far more organic.
Of course the process can also be reversed, allowing the curve to flow seamlessly from one space to another.
Here are far more complex examples of growth simulations exploring various rules and parameters:
6.0 Developing Fractal Curves
In the interest of creating something a little more tangible, it is possible to increase the dimension of these curves. Recording the progressive iterations of a space filling curve allow us to generate what is essentially a space-filling surface. This new surface has the unique quality of being able to fill a three-dimensional space of any shape and size, while being a single surface. It of course also shares the same qualities as its source curves, where it keep increasing in surface area (and can do so indefinitely).
If you were to keep gradually (but indefinitely) increasing the area of a surface this way in a finite space, the result will be a two-dimensional surface seamlessly transforming into a three-dimensional volume.
6.1 Dragon’s Feet
Here is an example of turning the dragon curve into a space-filling surface. Each iteration is recorded and offset in depth, all of which inform the generation of a surface that loosely flows through each of them. This was again achieved with Rhino and Grasshopper.
I don’t believe this geometry has a name beyond ‘the developing dragon curve’, so I’ve called it ‘Dragon’s Feet.’
Adding a little thickness to the model allow us to 3D print it.
6.2 Hilbert’s Curtain
Here is the Hilbert Curve going through the same process, which I am aptly naming ‘Hilbert’s Curtain.’
3D Printing Space-Filling Curves with Henry Segerman at Numberphile:
‘Developing Fractal Curves’ by Geoffrey Irving & Henry Segerman:
6.3 Developing Whale Curve
Unsurprisingly this can also be done with differentially grown curve. The respective difference being that this method fills a specific space in a less controlled manner.
In this case with Kangaroo 2 is used to grow a curve into the shape of a whale. Like before, each iteration is used to inform a single-surface geometry.
The Wishing Well
something caught in between dimensions – on its way to becoming more.
Summary
The Wishing Well is the physical manifestation, a snap-shot, of a creature caught in between dimensions – frozen in time. It is a digital entity that has been extracted from its home in the fractured planes of the mathematical realm; a differentially grown curve in bloom, organically filling space in the material world.
3D Printed Differential Space-Filling Curve
3D Printed Developing Hilbert Curve
The notion of geometry in between dimensions is explored in a previous post: Shapes, Fractals, Time & the Dimensions they Belong to
Description
The piece will be built from the bottom-up. Starting with the profile of a differentially grown curve (a squiggly line), an initial layer will be set in pieces of 2 x 4 inch wooden studs (38 x 89 millimeter profile) laid flat, and anchored to the ground. Each subsequent layer will be built upon and fixed to the last, where each new layer is a slightly smoother version than the last. 210 layers will be used to reach a height of 26 feet (8 meters). The horizontal spaces in between each of the pieces will automatically generate hand and foot holes, making the structure easily climbable. The footprint of the build will be bound to a space 32 x 32 feet.
The design may utilize two layers, inner and out, that meet at the top to increase the structural integrity for the whole build. It will be lit from within, either from the ground with spotlights or with LED strip lights following patterns along the walls.
Ambition
At the Wishing Well, visitors embark on a small journey, exploring the uniquely complex geometry of the structure before them. As they approach the foot of the well, it will stand towering above them, undulating organically across the landscape. The nature of the structure’s curves beckons visitors to explore the piece’s every nook and cranny. Moreover, its stature grants a certain degree of shelter to any traveller seeking refuge from the Playa’s extreme weather conditions. The well’s shape and scale allows natural, and artificial, light to interact in curious ways with the structure throughout the day and night. The horizontal gaps between every ‘brick’ in the wall allows light to filter through each layer, which in turn casts intriguing shadows across the desert. This perforation also allows Burners to easily, and relatively safely, scale the face of the build. Visitors will have the opportunity to grant a wish by writing it down on a tag and fixing it to the well’s interior.
Philosophy
If you had one magical (paradox free) wish, to do anything you like, what would it be?
Anything can be wished for at the Wishing Well, but a wish will not come true if it is deemed too greedy. Visitors must write their wish down on a tag and fix it to the inside of the well. They must choose wisely, as they are only allowed one. Additionally, they may choose to leave a single, precious, offering. However, if the offering does not burn, it will not be accepted. Visitors will also find that they must tread lightly on other people’s wishes and offerings.
The color of the tag and offering are important as they are associated with different meanings:
- ► PINK – love
- ► RED – happiness, joy, success, good luck, passion, vitality, celebration
- ► ORANGE – change, adaptability, spontaneity, concentration
- ► YELLOW – nourishment, warmth, clarity, empathy, being free from worldly cares
- ► GREEN – growth, balance, healing, self-assurance, benevolence, patience
- ► BLUE – conservation, healing, relaxation, exploration, trust, calmness
- ► PURPLE – spiritual awareness, physical and mental healing
- ► BLACK – profoundness, stability, knowledge, trust, adaptability, spontaneity,
- ► WHITE – mourning, righteousness, purity, confidence, intuition, spirits, courage
The Wishing Well is a physical manifestation of the wishes it holds. They are something caught in between – on their way to becoming more. I wish for guests to reflect on where they’ve been, where they are, where they are going, and where they wish to go.
Thursday 19th October Pin-Up
Diploma Studio 10 is back with 21 talented architecture students from 4th and 5th year working on the Brief01:Fractals. Here is an overview of their experiments so far after 4 weeks of workshops.
3 Days left to help us with the Tangential Dreams Crowdfunding Campaign
Hello WeWantToLearn community. We’re going to Burning Man in less than a month!
Our project this year will be a physical manifestation of our collective dreams and is called Tangential Dreams. It is a seven meters high temporary timber tower displaying inspiring messages from around the world, written on a multitude of swirling “tangents”.
We need your help to realise our project! There is only three days left to collect the missing £5,000 on our crowdfunding campaign to finance the many expenses associated with the creation of such an ambitious project.
Please click on the image below or use the following shortlink to share/help – everything helps: http://kck.st/28KlbPk 🙂
The project is a climbable sinuous tower made from off-the-shelf timber and digitally designed via algorithmic rules. One thousand “tangent” and light wooden pieces, stenciled with inspiring sentences, are strongly held in position by a helicoid sub-structure rotating along a central spine which also forms a safe staircase to climb on. Each one of the poetic branches faces a different angle, based on the tangent vectors of a sweeping sine curve. In line with this year’s theme, the piece is reminiscent of Leonardo’s Vitruvian man’s movement, helicoid inventions such as the “aerial screw” helicopter and Chambord castle helicoid staircase as well as his deep, systematic, understanding of the rules behind form to create art. From a wave to a flame all the way to a giant desert cactus, the complex simplicity of the art piece will trigger many interpretations, many dreams.
The art piece attempts to maximize an inexpensive material by using the output of an algorithm – (the value of the piece being the mathematics behind it, as well as the experience, not the materials being used). The computer outputs information to locate the column, sub-structure and tangents. We believe digital tools in design are giving rise to a new Renaissance, in which highly sophisticated designs, mimicking natural processes by integrating structural and environmental feedback, can be achieved at a very low cost. We worked very closely with our structural engineer format, sharing our algorithms, to give structural integrity to the piece and resist the strong climbing and wind loads. There are now three “legs” to our proposal, each rotated from each other at 60 degrees angles around a central solid spine, to ensure the stability of the piece, similarly to a tripod. The tangents are not just a decoration, they act as a spiky balustrade to prevent people from falling.
We have a fantastic team for the project: Philip Olivier, Eira Mooney, Maialen Calleja, Aaron Porterfield, Sebastian Morales, Antony Dobrzensky, Laura Nica, Karina Pitis, Hamish Macpherson, Jon Goodbun, Yannick Yamanga, Matthew Springer ,Josh NG ,Lola Chaine, Dror BenHay, Peter Wang, Charlotte Chambers, Michael DiCarlo, Sandy Kwan.
The Butterfly Egg
Geometry can be found on the smallest of scales, as is proven by the beautiful work of the butterfly in creating her eggs. The butterflies’ metamorphosis is a recognised story, but few know about the start of the journey. The egg from which the caterpillar emerges is in itself a magnificently beautiful object.
Geometry can be found on the smallest of scales, as is proven by the beautiful work of the butterfly in creating her eggs. The butterflies’ metamorphosis is a recognised story, but few know about the start of the journey. The egg from which the caterpillar emerges is in itself a magnificently beautiful object. The tiny eggs, barely visible to the naked eye, serve as home for the developing larva as well as their first meal.
![White Royal [Pratapa deva relata] HuDie's Microphotography](https://wewanttolearn.files.wordpress.com/2015/11/the-square-egg.jpg)
Each kind of butterfly has its unique egg design, creating a myriad of beautiful variations.
These are some of the typical shapes that each family produce.
But it is the Lycaenidae family that have the most geometrical and intricate eggs.
Biomimetics, or biomimicry is an exciting concept that suggests that every field and industry has something to learn from the natural world. The story of evolution is full of problems that have been innovatively solved.
There are thousands of species of butterfly, each with their unique egg design. 
A truncated icosahedron for a frame, the opposite of a football. Instead of panels pushed out, they are pulled in.
Fractals are commonly occurring in nature, and can be described as a never-ending pattern on different scales. People are subconsciously familiar with fractals, so are inherently more relaxed when surrounded by them.
3D Printing is a relatively new technology that is set to change our world. Innovations in the uses of 3D printers, combined with falling costs, means that they could be a ubiquitous tool in every home and industry. 3D printers and scanners are already used a great deal in everything from the biomedical field to art studios, and experiments are currently being done to construct entire homes. This technology is in its infancy, and it is exactly for this reason that every effort should be taken to research its potential. It is common to use 3D printers in architecture to show small working models, I would like to now use it to make a large and complex structure at full scale.
This research will underpin the design of a sculptural installation in which people can interact with live butterflies. With the ever-declining numbers of butterflies worldwide and in the UK, conservation and education are paramount.
The link between butterflies and humans in our ecosystem is one that is vital and should be conserved and celebrated.
I can imagine an ethereal space filled with dappled light where people can come for contemplation and perhaps their own personal metamorphosis.
—Tia
Scherk’s Minimal Surface
In mathematics, a Scherk surface (named after Heinrich Scherk in 1834) is an example of a minimal surface. A minimal surface is a surface that locally minimizes its area (or having a mean curvature of zero). The classical minimal surfaces of H.F. Scherk were initially an attempt to solve Gergonne’s problem, a boundary value problem in the cube.
The term ‘minimal surface’ is used because these surfaces originally arose as surfaces that minimized total surface area subject to some constraint. Physical models of area-minimizing minimal surfaces can be made by dipping a wire frame into a soap solution, forming a soap film, which is a minimal surface whose boundary is the wire frame. However the term is used for more general surfaces that may self-intersect or do not have constraints. For a given constraint there may also exist several minimal surfaces with different areas (for example, minimal surface of revolution, Saddle Towers etc.).
Scherk’s minimal surface arises from the solution to a differential equation that describes a minimal monge patch (a patch that maps [u, v] to [u, v, f(u, v)]). The full surface is obtained by putting a large number the small units next to each other in a chessboard pattern. The plots were made by plotting the implicit definition of the surface.
An implicit formula for the Scherk tower is:
sin(x) · sin(z) = sin(y),
where x, y and z denote the usual coordinates of R3.
Scherk’s second surface can be written parametrically as:
x = ln((1+r²+2rcosθ)/(1+r²-2rcosθ))
y = ((1+r²-2rsinθ)/(1+r²+2rsinθ))
z = 2tan-1[(2r²sin(2θ))/(r-1)]
for θ in [0,2), and r in (0,1).
Scherk described two complete embedded minimal surfaces in 1834; his first surface is a doubly periodic surface, his second surface is singly periodic. They were the third non-trivial examples of minimal surfaces (the first two were the catenoid and helicoid). The two surfaces are conjugates of each other.
Scherk’s first surface
Scherk’s first surface is asymptotic to two infinite families of parallel planes, orthogonal to each other, that meet near z = 0 in a checkerboard pattern of bridging arches. It contains an infinite number of straight vertical lines.
Scherk’s second surface
Scherk’s second surface looks globally like two orthogonal planes whose intersection consists of a sequence of tunnels in alternating directions. Its intersections with horizontal planes consists of alternating hyperbolas.
Other types are:
- The doubly periodic Scherk surface
- The Karcher-Scherk surface
- The sheared (Karcher-)Scherk surface
- The doubly periodic Scherk surface with handles
- The Meeks-Rosenberg surfaces
Scherk’s surface can have many iterations, according to the number of saddle branches, number of holes, turn around the axis and bends towards the axis. Some of the design iterations and adaptations of the system are presented below:
Scherk’s Surface can be adapted to several design possibilities, with multiple ways of fabrication. Interlocked slices using laser cut plywood sheets, folded planes of metal or CNC stacked wooden slices. With its versatile and flexible form it is adaptable to any interior space as an installation or temporary furniture.
