Wednesday, October 5, 2011
Course Synopsis
The presence of advanced design techniques in architecture has resulted in a body of work driven by anexact yet rigorous geometries. These geometric language bears a relation to forms in nature, which are driven by a variety of environmental impacts such as gravity, radiation, molecular bonding and weather conditions. The resulting geometries are splendid examples of intricate and effective conditions of sustainability. The elective Sustainable Concepts in Advanced Design will explore the relation between digital design techniques, spatial performance, synthetic ecologies and the integration of strategies of sustainability based on contemporary insights in the natural sciences. The speculative nature of the elective will allow for the application of the research to a variety of scales up to the level of urban conditions. The research will include issues such as geometries in nature, performative surfaces, economy of form and architectonic metabolism.
Tuesday, July 14, 2009
Geometry in Nature
Fibonacci Number
Overview
In mathematics, the Fibonacci numbers are the following sequence of numbers:
0,1 ,1 ,2 ,3 ,5 ,8 ,13 ,21 ,34 ,55 ,89 ....
By definition, the first two Fibonacci numbers are 0 and 1, and each remaining number is the sum of the previous two. Some sources omit the initial 0, instead beginning the sequence with two 1s.
In mathematical terms, the sequence Fn of Fibonacci numbers is defined by the recurrence relation
F_n = F_{n-1} + F_{n-2}
with seed values
F_0 = 0 and F_1 = 1.
The Fibonacci sequence is named after Leonardo of Pisa, who was known as Fibonacci (a contraction of filius Bonaccio, "son of Bonaccio".) Fibonacci's 1202 book Liber Abaci introduced the sequence to Western European mathematics, although the sequence had been previously described in Indian mathematics.
Origins
The Fibonacci sequence was well known in ancient India, where it was applied to the metrical sciences (prosody), long before it was known in Europe. Developments have been attributed to Pingala (200 BC), Virahanka (6th century AD), Gopāla (c.1135 AD), and Hemachandra (c.1150 AD).
The Fibonacci sequence is formed by adding S to a pattern of length n − 1, or L to a pattern of length n − 2; and the prosodicists showed that the number of patterns of length n is the sum of the two previous numbers in the sequence. Donald Knuth reviews this work in The Art of Computer Programming.
In the West, the sequence was studied by Leonardo of Pisa, known as Fibonacci, in his Liber Abaci (1202). He considers the growth of an idealised (biologically unrealistic) rabbit population, assuming that:
* In the "zeroth" month, there is one pair of rabbits (additional pairs of rabbits = 0).
* In the first month, the first pair begets another pair (additional pairs of rabbits = 1).
* In the second month, both pairs of rabbits have another pair, and the first pair dies (additional pairs of rabbits = 1).
* In the third month, the second pair and the new two pairs have a total of three new pairs, and the older second pair dies (additional pairs of rabbits = 2).
The laws of this are that each pair of rabbits has 2 pairs in its lifetime, and dies.
Let the population at month n be F(n). At this time, only rabbits who were alive at month n − 2 are fertile and produce offspring, so F(n − 2) pairs are added to the current population of F(n − 1). Thus the total is F(n) = F(n − 1) + F(n − 2).
List of fibonacci numbers
The first 21 Fibonacci numbers (sequence A000045 in OEIS), also denoted as Fn, for n = 0, 1, 2, ... ,20 are:
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765
Using the recurrence relation, the sequence can also be extended to negative index n. Thus the complete sequence is
..., -8, 5, -3, 2 , -1, 1, 0, 1, 1, 2, 3, 5, 8, ...
A tiling with squares whose sides are successive Fibonacci numbers in length
A yupana (Quechua for "counting tool") is a calculator which was used by the Incas. Researchers assume that calculations were based on Fibonacci numbers to minimize the number of necessary grains per field. ( source :http://www.quipus.it/english/Andean%20Calculators.pdf)
A Fibonacci spiral created by drawing arcs connecting the opposite corners of squares in the Fibonacci tiling; this one uses squares of sizes 1, 1, 2, 3, 5, 8, 13, 21, and 34;
( Source: www.wikipedia.org)
Fibonacci numbers in nature
Fibonacci sequences appear in biological settings, in two consecutive Fibonacci numbers, such as branching in trees, arrangement of leaves on a stem, the fruitlets of a pineapple, the flowering of artichoke, an uncurling fern and the arrangement of a pine cone. In addition, numerous poorly substantiated claims of Fibonacci numbers or golden sections in nature are found in popular sources, e.g. relating to the breeding of rabbits, the spirals of shells, and the curve of waves. The Fibonacci numbers are also found in the family tree of honeybees.
examples are given below :
a) Petals on flowers
Probably most of us have never taken the time to examine very carefully the number or arrangement of petals on a flower. If we were to do so, we would find that the number of petals on a flower, that still has all of its petals intact and has not lost any, for many flowers is a Fibonacci number:
* 3 petals: lily, iris
* 5 petals: buttercup, wild rose, larkspur, columbine (aquilegia)
* 8 petals: delphiniums
* 13 petals: ragwort, corn marigold, cineraria,
* 21 petals: aster, black-eyed susan, chicory
* 34 petals: plantain, pyrethrum
* 55, 89 petals: michaelmas daisies, the asteraceae family
Some species are very precise about the number of petals they have - e.g. buttercups, but others have petals that are very near those above, with the average being a Fibonacci number.
1 petalled_white calla lily
2 petalled_euphorbia
3 petalled_trillium
5 petalled_ columbine
8 petalled_ bloodroot
13 petalled_ black eyed susan
21 petalled_ shasta daisy
34 petalled_ field daisies
(source: britton.disted.camosun.bc.ca)
b) Arrangement of leaves on a stem
phyllotaxis (the spiral arrangement of the leaves on the stem of a plant)
source: dangerousintersection.org
c) In vegetables and fruits
Romanesque Brocolli/Cauliflower (or Romanesco) looks and tastes like a cross between brocolli and cauliflower. Each floret is peaked and is an identical but smaller version of the whole thing and this makes the spirals easy to see.
Brocolli/Cauliflower ( source: www.world-mysteries.com)
d) Arrangement of pine cones
From Pine Cones to Cones and Fibonacci Connections
(source: www.crystalinks.com/pineconesfibonacci.html)
e) Flower Patterns and Fibonacci Numbers
Why is it that the number of petals in a flower is often one of the following numbers: 3, 5, 8, 13, 21, 34 or 55? For example, the lily has three petals, buttercups have five of them, the chicory has 21 of them, the daisy has often 34 or 55 petals, etc. Furthermore, when one observes the heads of sunflowers, one notices two series of curves, one winding in one sense and one in another; the number of spirals not being the same in each sense. Why is the number of spirals in general either 21 and 34, either 34 and 55, either 55 and 89, or 89 and 144? The same for pinecones : why do they have either 8 spirals from one side and 13 from the other, or either 5 spirals from one side and 8 from the other? Finally, why is the number of diagonals of a pineapple also 8 in one direction and 13 in the other?
Passion fruit
Are these numbers the product of chance? No! They all belong to the Fibonacci sequence: 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, etc. (where each number is obtained from the sum of the two preceding). A more abstract way of putting it is that the Fibonacci numbers fn are given by the formula f1 = 1, f2 = 2, f3 = 3, f4 = 5 and generally f n+2 = fn+1 + fn . For a long time, it had been noticed that these numbers were important in nature, but only relatively recently that one understands why. It is a question of efficiency during the growth process of plants.
The explanation is linked to another famous number, the golden mean, itself intimately linked to the spiral form of certain types of shell. Let's mention also that in the case of the sunflower, the pineapple and of the pinecone, the correspondence with the Fibonacci numbers is very exact, while in the case of the number of flower petals, it is only verified on average (and in certain cases, the number is doubled since the petals are arranged on two levels).
sunflower
f) Human hand
Every human has two hands, each one of these has five fingers, each finger has three parts which are separated by two knuckles. All of these numbers fit into the sequence. However keep in mind, this could simply be coincidence.
g) Human face
Knowledge of the golden section, ratio and rectangle goes back to the Greeks, who based their most famous work of art on them: the Parthenon is full of golden rectangles. The Greek followers of the mathematician and mystic Pythagoras even thought of the golden ratio as divine.
Later, Leonardo da Vinci painted Mona Lisa's face to fit perfectly into a golden rectangle, and structured the rest of the painting around similar rectangles.
Mozart divided a striking number of his sonatas into two parts whose lengths reflect the golden ratio, though there is much debate about whether he was conscious of this. In more modern times, Hungarian composer Bela Bartok and French architect Le Corbusier purposefully incorporated the golden ratio into their work.
Even today, the golden ratio is in human-made objects all around us. Look at almost any Christian cross; the ratio of the vertical part to the horizontal is the golden ratio. To find a golden rectangle, you need to look no further than the credit cards in your wallet.
Despite these numerous appearances in works of art throughout the ages, there is an ongoing debate among psychologists about whether people really do perceive the golden shapes, particularly the golden rectangle, as more beautiful than other shapes. In a 1995 article in the journal Perception, professor Christopher Green, of York University in Toronto, discusses several experiments over the years that have shown no measurable preference for the golden rectangle, but notes that several others have provided evidence suggesting such a preference exists.
Regardless of the science, the golden ratio retains a mystique, partly because excellent approximations of it turn up in many unexpected places in nature. The spiral inside a nautilus shell is remarkably close to the golden section, and the ratio of the lengths of the thorax and abdomen in most bees is nearly the golden ratio. Even a cross section of the most common form of human DNA fits nicely into a golden decagon. The golden ratio and its relatives also appear in many unexpected contexts in mathematics, and they continue to spark interest in the mathematical community.
Dr. Stephen Marquardt, a former plastic surgeon, has used the golden section, that enigmatic number that has long stood for beauty, and some of its relatives to make a mask that he claims is the most beautiful shape a human face can have.
The Mask of a perfect human
Egyptian Queen Nefertiti
An artist's impression of the face of Jesus based on the Shroud of Turin and corrected to match Dr. Stephen Marquardt's mask.
Fibonacci's Rabbits
The original problem that Fibonacci investigated, in the year 1202, was about how fast rabbits could breed in ideal circumstances. "A pair of rabbits, one month old, is too young to reproduce. Suppose that in their second month, and every month thereafter, they produce a new pair. If each new pair of rabbits does the same, and none of the rabbits dies, how many pairs of rabbits will there be at the beginning of each month?"
1. At the end of the first month, they mate, but there is still one only 1 pair.
2. At the end of the second month the female produces a new pair, so now there are 2 pairs of rabbits in the field.
3. At the end of the third month, the original female produces a second pair, making 3 pairs in all in the field.
4. At the end of the fourth month, the original female has produced yet another new pair, the female born two months ago produces her first pair also, making 5 pairs. (http://www.mcs.surrey.ac.uk/Personal/R.Knott/Fibonacci/fibBio.html)
The number of pairs of rabbits in the field at the start of each month is 1, 1, 2, 3, 5, 8, 13, 21, etc.
The Fibonacci Rectangles and Shell Spirals
We can make another picture showing the Fibonacci numbers 1,1,2,3,5,8,13,21,.. if we start with two small squares of size 1 next to each other. On top of both of these draw a square of size 2 (=1+1).
Phi pendant gold - a Powerful Tool for Finding
We can now draw a new square - touching both a unit square and the latest square of side 2 - so having sides 3 units long; and then another touching both the 2-square and the 3-square (which has sides of 5 units). We can continue adding squares around the picture, each new square having a side which is as long as the sum of the latest two square's sides. This set of rectangles whose sides are two successive Fibonacci numbers in length and which are composed of squares with sides which are Fibonacci numbers, we will call the Fibonacci Rectangles.
The next diagram shows that we can draw a spiral by putting together quarter circles, one in each new square. This is a spiral (the Fibonacci Spiral). A similar curve to this occurs in nature as the shape of a snail shell or some sea shells. Whereas the Fibonacci Rectangles spiral increases in size by a factor of Phi (1.618..) in a quarter of a turn (i.e. a point a further quarter of a turn round the curve is 1.618... times as far from the centre, and this applies to all points on the curve), the Nautilus spiral curve takes a whole turn before points move a factor of 1.618... from the centre.
A slice through a Nautilus shell
These spiral shapes are called Equiangular or Logarithmic spirals. The links from these terms contain much more information on these curves and pictures of computer-generated shells.
Here is a curve which crosses the X-axis at the Fibonacci numbers
The spiral part crosses at 1 2 5 13 etc on the positive axis, and 0 1 3 8 etc on the negative axis. The oscillatory part crosses at 0 1 1 2 3 5 8 13 etc on the positive axis. The curve is strangely reminiscent of the shells of Nautilus and snails. This is not surprising, as the curve tends to a logarithmic spiral as it expands.
Nautilus shell (cut)
Golden Ratio & Golden Section : : Golden Rectangle : :
Golden Ratio & Golden Section
In mathematics and the arts, two quantities are in the golden ratio if the ratio between the sum of those quantities and the larger one is the same as the ratio between the larger one and the smaller.
Expressed algebraically:
The golden ratio is often denoted by the Greek letter phi (Φ or φ).
The figure of a golden section illustrates the geometric relationship that defines this constant. The golden ratio is an irrational mathematical constant, approximately 1.6180339887.
Golden Rectangle
A golden rectangle is a rectangle whose side lengths are in the golden ratio, 1: j (one-to-phi),
that is, 1 : or approximately 1:1.618.
A golden rectangle can be constructed with only straightedge and compass by this technique:
1. Construct a simple square
2. Draw a line from the midpoint of one side of the square to an opposite corner
3. Use that line as the radius to draw an arc that defines the height of the rectangle
4. Complete the golden rectangle
Golden Spiral
In geometry, a golden spiral is a logarithmic spiral whose growth factor b is related to j, the golden ratio. Specifically, a golden spiral gets wider (or further from its origin) by a factor of j for every quarter turn it makes.
Successive points dividing a golden rectangle into squares lie on
a logarithmic spiral which is sometimes known as the golden spiral.
Image Source: http://mathworld.wolfram.com/GoldenRatio.html
Proportion - Golden Ratio and Rule of Thirds
Proportion refers the size relationship of visual elements to each other and to the whole picture. One of the reasons proportion is often considered important in composition is that viewers respond to it emotionally. Proportion in art has been examined for hundreds of years, long before photography was invented. One proportion that is often cited as occurring frequently in design is the Golden mean or Golden ratio.
Golden Ratio: 1, 1, 2, 3, 5, 8, 13, 21, 34 etc. Each succeeding number after 1 is equal to the sum of the two preceding numbers. The Ratio formed 1:1.618 is called the golden mean - the ratio of bc to ab is the same as ab to ac. If you divide each smaller window again with the same ratio and joing their corners you end up with a logarithmic spiral. This spiral is a motif found frequently throughout nature in shells, horns and flowers (and my Science & Art logo).
The Golden Mean or Phi occurs frequently in nature and it may be that humans are genetically programmed to recognize the ratio as being pleasing. Studies of top fashion models revealed that their faces have an abundance of the 1.618 ratio.
Tlc.discovery.com/convergence/humanface/articles/mask.html
Many photographers and artists are aware of the rule of thirds, where a picture is divided into three sections vertically and horizontally and lines and points of intersection represent places to position important visual elements. The golden ratio and its application are similar although the golden ratio is not as well known and its' points of intersection are closer together. Moving a horizon in a landscape to the position of one third is often more effective than placing it in the middle, but it could also be placed near the bottom one quarter or sixth. There is nothing obligatory about applying the rule of thirds. In placing visual elements for effective composition, one must assess many factors including color, dominance, size and balance together with proportion. Often a certain amount of imbalance or tension can make an image more effective. This is where we come to the artists' intuition and feelings about their subject. Each of us is unique and we should strive to preserve those feelings and impressions about our chosen subject that are different.
Golden mean grid applied a simple composition
On analyzing some of my favorite photographs by laying down grids (thirds or golden ratio in Adobe Photoshop) I find that some of my images do indeed seem to correspond to the rule of thirds and to a lesser extent the golden ratio, however many do not. I suspect an analysis of other photographers' images would have similar results. There are a few web sites and references to scientific studies that have studied proportion in art and photography but I have not come across any systematic studies that quantified their results- maybe I just need to look harder (see link for more information about the use of the golden ratio: http://photoinf.com/Golden_Mean/).
In summary, proportion is an element of design you should always be aware of but you must also realize that other design factors along with your own unique sensitivity about the subject dictates where you should place items in the viewfinder. Understanding proportion and various elements of design are guidelines only and you should always follow your instincts combined with your knowledge. Never be afraid to experiment and try something drastically different, and learn from both your successes and failures. Also try to be open minded about new ways of taking pictures, new techniques, ideas - surround yourself with others that share an open mind and enthusiasm and you will improve your compositional skills quickly.
35 mm film has the dimensions 36 mm by 24 mm (3:2 ratio) - golden mean ration of 1.6 to 1 Points of intersection are recommended as places to position important elements in your picture.
Golden Ratio in Nature
Adolf Zeising, whose main interests were mathematics and philosophy, found the golden ratio expressed in the arrangement of branches along the stems of plants and of veins in leaves. He extended his research to the skeletons of animals and the branchings of their veins and nerves, to the proportions of chemical compounds and the geometry of crystals, even to the use of proportion in artistic endeavors. In these phenomena he saw the golden ratio operating as a universal law.[38] Zeising wrote in 1854:
The Golden Ratio is a universal law in which is contained the ground-principle of all formative striving for beauty and completeness in the realms of both nature and art, and which permeates, as a paramount spiritual ideal, all structures, forms and proportions, whether cosmic or individual, organic or inorganic, acoustic or optical; which finds its fullest realization, however, in the human form.
Source: http://www.xgoldensection.com/xgoldensection.html
Source:: http://www.goldennumber.net/hand.htm
A slice through a Nautilus shell reveals golden spiral construction principle.
The effectiveness of the Golden Mean
The explanation which follows is very succinct. For a much more detailed explanation, with very interesting animations, see the web site in the reference.
In many cases, the head of a flower is made up of small seeds which are produced at the centre, and then migrate towards the outside to fill eventually all the space (as for the sunflower but on a much smaller level). Each new seed appears at a certain angle in relation to the preceeding one. For example, if the angle is 90 degrees, that is 1/4 of a turn, the result after several generations is that represented by figure 1.
Of course, this is not the most efficient way of filling space. In fact, if the angle between the appearance of each seed is a portion of a turn which corresponds to a simple fraction, 1/3, 1/4, 3/4, 2/5, 3/7, etc (that is a simple rational number), one always obtains a series of straight lines. If one wants to avoid this rectilinear pattern, it is necessary to choose a portion of the circle which is an irrational number (or a nonsimple fraction). If this latter is well approximated by a simple fraction, one obtains a series of curved lines (spiral arms) which even then do not fill out the space perfectly (figure 2).
In order to optimize the filling, it is necessary to choose the most irrational number there is, that is to say, the one the least well approximated by a fraction. This number is exactly the golden mean. The corresponding angle, the golden angle, is 137.5 degrees. (It is obtained by multiplying the non-whole part of the golden mean by 360 degrees and, since one obtains an angle greater than 180 degrees, by taking its complement). With this angle, one obtains the optimal filling, that is, the same spacing between all the seeds (figure 3).
This angle has to be chosen very precisely: variations of 1/10 of a degree destroy completely the optimization. (In fig 2, the angle is 137.6 degrees!) When the angle is exactly the golden mean, and only this one, two families of spirals (one in each direction) are then visible: their numbers correspond to the numerator and denominator of one of the fractions which approximates the golden mean : 2/3, 3/5, 5/8, 8/13, 13/21, etc.
These numbers are precisely those of the Fibonacci sequence (the bigger the numbers, the better the approximation) and the choice of the fraction depends on the time laps between the appearance of each of the seeds at the center of the flower.
This is why the number of spirals in the centers of sunflowers, and in the centers of flowers in general, correspond to a Fibonacci number. Moreover, generally the petals of flowers are formed at the extremity of one of the families of spiral. This then is also why the number of petals corresponds on average to a Fibonacci number.
Golden Ratio in Architecture and Art
Many architects and artists have proportioned their works to approximate the golden ratio—especially in the form of the golden rectangle, in which the ratio of the longer side to the shorter is the golden ratio—believing this proportion to be aesthetically pleasing. [Source: Wikipedia.org]
Here are few examples:
Parthenon, Acropolis, Athens. This ancient temple fits almost precisely into a golden rectangle.
Source: http://britton.disted.camosun.bc.ca/goldslide/jbgoldslide.htm
The Vetruvian Man"(The Man in Action)" by Leonardo Da Vinci .We can draw many lines of the rectangles into this figure. Then, there are three distinct sets of Golden Rectangles: Each one set for the head area, the torso, and the legs.
Leonardo's Vetruvian Man is sometimes confused with principles of "golden rectangle", however that is not the case. The construction of Vetruvian Man is based on drawing a circle with its diameter equal to diagonal of the square, moving it up so it would touch the base of the square and drawing the final circle between the base of the square and the mid-point between square's center and center of the moved circle.
Source : www.world-mysteries.com
Overview
In mathematics, the Fibonacci numbers are the following sequence of numbers:
0,1 ,1 ,2 ,3 ,5 ,8 ,13 ,21 ,34 ,55 ,89 ....
By definition, the first two Fibonacci numbers are 0 and 1, and each remaining number is the sum of the previous two. Some sources omit the initial 0, instead beginning the sequence with two 1s.
In mathematical terms, the sequence Fn of Fibonacci numbers is defined by the recurrence relation
F_n = F_{n-1} + F_{n-2}
with seed values
F_0 = 0 and F_1 = 1.
The Fibonacci sequence is named after Leonardo of Pisa, who was known as Fibonacci (a contraction of filius Bonaccio, "son of Bonaccio".) Fibonacci's 1202 book Liber Abaci introduced the sequence to Western European mathematics, although the sequence had been previously described in Indian mathematics.
Origins
The Fibonacci sequence was well known in ancient India, where it was applied to the metrical sciences (prosody), long before it was known in Europe. Developments have been attributed to Pingala (200 BC), Virahanka (6th century AD), Gopāla (c.1135 AD), and Hemachandra (c.1150 AD).
The Fibonacci sequence is formed by adding S to a pattern of length n − 1, or L to a pattern of length n − 2; and the prosodicists showed that the number of patterns of length n is the sum of the two previous numbers in the sequence. Donald Knuth reviews this work in The Art of Computer Programming.
In the West, the sequence was studied by Leonardo of Pisa, known as Fibonacci, in his Liber Abaci (1202). He considers the growth of an idealised (biologically unrealistic) rabbit population, assuming that:
* In the "zeroth" month, there is one pair of rabbits (additional pairs of rabbits = 0).
* In the first month, the first pair begets another pair (additional pairs of rabbits = 1).
* In the second month, both pairs of rabbits have another pair, and the first pair dies (additional pairs of rabbits = 1).
* In the third month, the second pair and the new two pairs have a total of three new pairs, and the older second pair dies (additional pairs of rabbits = 2).
The laws of this are that each pair of rabbits has 2 pairs in its lifetime, and dies.
Let the population at month n be F(n). At this time, only rabbits who were alive at month n − 2 are fertile and produce offspring, so F(n − 2) pairs are added to the current population of F(n − 1). Thus the total is F(n) = F(n − 1) + F(n − 2).
List of fibonacci numbers
The first 21 Fibonacci numbers (sequence A000045 in OEIS), also denoted as Fn, for n = 0, 1, 2, ... ,20 are:
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765
Using the recurrence relation, the sequence can also be extended to negative index n. Thus the complete sequence is
..., -8, 5, -3, 2 , -1, 1, 0, 1, 1, 2, 3, 5, 8, ...
A tiling with squares whose sides are successive Fibonacci numbers in length
A yupana (Quechua for "counting tool") is a calculator which was used by the Incas. Researchers assume that calculations were based on Fibonacci numbers to minimize the number of necessary grains per field. ( source :http://www.quipus.it/english/Andean%20Calculators.pdf)
A Fibonacci spiral created by drawing arcs connecting the opposite corners of squares in the Fibonacci tiling; this one uses squares of sizes 1, 1, 2, 3, 5, 8, 13, 21, and 34;
( Source: www.wikipedia.org)
Fibonacci numbers in nature
Fibonacci sequences appear in biological settings, in two consecutive Fibonacci numbers, such as branching in trees, arrangement of leaves on a stem, the fruitlets of a pineapple, the flowering of artichoke, an uncurling fern and the arrangement of a pine cone. In addition, numerous poorly substantiated claims of Fibonacci numbers or golden sections in nature are found in popular sources, e.g. relating to the breeding of rabbits, the spirals of shells, and the curve of waves. The Fibonacci numbers are also found in the family tree of honeybees.
examples are given below :
a) Petals on flowers
Probably most of us have never taken the time to examine very carefully the number or arrangement of petals on a flower. If we were to do so, we would find that the number of petals on a flower, that still has all of its petals intact and has not lost any, for many flowers is a Fibonacci number:
* 3 petals: lily, iris
* 5 petals: buttercup, wild rose, larkspur, columbine (aquilegia)
* 8 petals: delphiniums
* 13 petals: ragwort, corn marigold, cineraria,
* 21 petals: aster, black-eyed susan, chicory
* 34 petals: plantain, pyrethrum
* 55, 89 petals: michaelmas daisies, the asteraceae family
Some species are very precise about the number of petals they have - e.g. buttercups, but others have petals that are very near those above, with the average being a Fibonacci number.
1 petalled_white calla lily
2 petalled_euphorbia
3 petalled_trillium
5 petalled_ columbine
8 petalled_ bloodroot
13 petalled_ black eyed susan
21 petalled_ shasta daisy
34 petalled_ field daisies
(source: britton.disted.camosun.bc.ca)
b) Arrangement of leaves on a stem
phyllotaxis (the spiral arrangement of the leaves on the stem of a plant)
source: dangerousintersection.org
c) In vegetables and fruits
Romanesque Brocolli/Cauliflower (or Romanesco) looks and tastes like a cross between brocolli and cauliflower. Each floret is peaked and is an identical but smaller version of the whole thing and this makes the spirals easy to see.
Brocolli/Cauliflower ( source: www.world-mysteries.com)
d) Arrangement of pine cones
From Pine Cones to Cones and Fibonacci Connections
(source: www.crystalinks.com/pineconesfibonacci.html)
e) Flower Patterns and Fibonacci Numbers
Why is it that the number of petals in a flower is often one of the following numbers: 3, 5, 8, 13, 21, 34 or 55? For example, the lily has three petals, buttercups have five of them, the chicory has 21 of them, the daisy has often 34 or 55 petals, etc. Furthermore, when one observes the heads of sunflowers, one notices two series of curves, one winding in one sense and one in another; the number of spirals not being the same in each sense. Why is the number of spirals in general either 21 and 34, either 34 and 55, either 55 and 89, or 89 and 144? The same for pinecones : why do they have either 8 spirals from one side and 13 from the other, or either 5 spirals from one side and 8 from the other? Finally, why is the number of diagonals of a pineapple also 8 in one direction and 13 in the other?
Passion fruit
Are these numbers the product of chance? No! They all belong to the Fibonacci sequence: 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, etc. (where each number is obtained from the sum of the two preceding). A more abstract way of putting it is that the Fibonacci numbers fn are given by the formula f1 = 1, f2 = 2, f3 = 3, f4 = 5 and generally f n+2 = fn+1 + fn . For a long time, it had been noticed that these numbers were important in nature, but only relatively recently that one understands why. It is a question of efficiency during the growth process of plants.
The explanation is linked to another famous number, the golden mean, itself intimately linked to the spiral form of certain types of shell. Let's mention also that in the case of the sunflower, the pineapple and of the pinecone, the correspondence with the Fibonacci numbers is very exact, while in the case of the number of flower petals, it is only verified on average (and in certain cases, the number is doubled since the petals are arranged on two levels).
sunflower
f) Human hand
Every human has two hands, each one of these has five fingers, each finger has three parts which are separated by two knuckles. All of these numbers fit into the sequence. However keep in mind, this could simply be coincidence.
g) Human face
Knowledge of the golden section, ratio and rectangle goes back to the Greeks, who based their most famous work of art on them: the Parthenon is full of golden rectangles. The Greek followers of the mathematician and mystic Pythagoras even thought of the golden ratio as divine.
Later, Leonardo da Vinci painted Mona Lisa's face to fit perfectly into a golden rectangle, and structured the rest of the painting around similar rectangles.
Mozart divided a striking number of his sonatas into two parts whose lengths reflect the golden ratio, though there is much debate about whether he was conscious of this. In more modern times, Hungarian composer Bela Bartok and French architect Le Corbusier purposefully incorporated the golden ratio into their work.
Even today, the golden ratio is in human-made objects all around us. Look at almost any Christian cross; the ratio of the vertical part to the horizontal is the golden ratio. To find a golden rectangle, you need to look no further than the credit cards in your wallet.
Despite these numerous appearances in works of art throughout the ages, there is an ongoing debate among psychologists about whether people really do perceive the golden shapes, particularly the golden rectangle, as more beautiful than other shapes. In a 1995 article in the journal Perception, professor Christopher Green, of York University in Toronto, discusses several experiments over the years that have shown no measurable preference for the golden rectangle, but notes that several others have provided evidence suggesting such a preference exists.
Regardless of the science, the golden ratio retains a mystique, partly because excellent approximations of it turn up in many unexpected places in nature. The spiral inside a nautilus shell is remarkably close to the golden section, and the ratio of the lengths of the thorax and abdomen in most bees is nearly the golden ratio. Even a cross section of the most common form of human DNA fits nicely into a golden decagon. The golden ratio and its relatives also appear in many unexpected contexts in mathematics, and they continue to spark interest in the mathematical community.
Dr. Stephen Marquardt, a former plastic surgeon, has used the golden section, that enigmatic number that has long stood for beauty, and some of its relatives to make a mask that he claims is the most beautiful shape a human face can have.
The Mask of a perfect human
Egyptian Queen Nefertiti
An artist's impression of the face of Jesus based on the Shroud of Turin and corrected to match Dr. Stephen Marquardt's mask.
Fibonacci's Rabbits
The original problem that Fibonacci investigated, in the year 1202, was about how fast rabbits could breed in ideal circumstances. "A pair of rabbits, one month old, is too young to reproduce. Suppose that in their second month, and every month thereafter, they produce a new pair. If each new pair of rabbits does the same, and none of the rabbits dies, how many pairs of rabbits will there be at the beginning of each month?"
1. At the end of the first month, they mate, but there is still one only 1 pair.
2. At the end of the second month the female produces a new pair, so now there are 2 pairs of rabbits in the field.
3. At the end of the third month, the original female produces a second pair, making 3 pairs in all in the field.
4. At the end of the fourth month, the original female has produced yet another new pair, the female born two months ago produces her first pair also, making 5 pairs. (http://www.mcs.surrey.ac.uk/Personal/R.Knott/Fibonacci/fibBio.html)
The number of pairs of rabbits in the field at the start of each month is 1, 1, 2, 3, 5, 8, 13, 21, etc.
The Fibonacci Rectangles and Shell Spirals
We can make another picture showing the Fibonacci numbers 1,1,2,3,5,8,13,21,.. if we start with two small squares of size 1 next to each other. On top of both of these draw a square of size 2 (=1+1).
Phi pendant gold - a Powerful Tool for Finding
We can now draw a new square - touching both a unit square and the latest square of side 2 - so having sides 3 units long; and then another touching both the 2-square and the 3-square (which has sides of 5 units). We can continue adding squares around the picture, each new square having a side which is as long as the sum of the latest two square's sides. This set of rectangles whose sides are two successive Fibonacci numbers in length and which are composed of squares with sides which are Fibonacci numbers, we will call the Fibonacci Rectangles.
The next diagram shows that we can draw a spiral by putting together quarter circles, one in each new square. This is a spiral (the Fibonacci Spiral). A similar curve to this occurs in nature as the shape of a snail shell or some sea shells. Whereas the Fibonacci Rectangles spiral increases in size by a factor of Phi (1.618..) in a quarter of a turn (i.e. a point a further quarter of a turn round the curve is 1.618... times as far from the centre, and this applies to all points on the curve), the Nautilus spiral curve takes a whole turn before points move a factor of 1.618... from the centre.
A slice through a Nautilus shell
These spiral shapes are called Equiangular or Logarithmic spirals. The links from these terms contain much more information on these curves and pictures of computer-generated shells.
Here is a curve which crosses the X-axis at the Fibonacci numbers
The spiral part crosses at 1 2 5 13 etc on the positive axis, and 0 1 3 8 etc on the negative axis. The oscillatory part crosses at 0 1 1 2 3 5 8 13 etc on the positive axis. The curve is strangely reminiscent of the shells of Nautilus and snails. This is not surprising, as the curve tends to a logarithmic spiral as it expands.
Nautilus shell (cut)
Golden Ratio & Golden Section : : Golden Rectangle : :
Golden Ratio & Golden Section
In mathematics and the arts, two quantities are in the golden ratio if the ratio between the sum of those quantities and the larger one is the same as the ratio between the larger one and the smaller.
Expressed algebraically:
The golden ratio is often denoted by the Greek letter phi (Φ or φ).
The figure of a golden section illustrates the geometric relationship that defines this constant. The golden ratio is an irrational mathematical constant, approximately 1.6180339887.
Golden Rectangle
A golden rectangle is a rectangle whose side lengths are in the golden ratio, 1: j (one-to-phi),
that is, 1 : or approximately 1:1.618.
A golden rectangle can be constructed with only straightedge and compass by this technique:
1. Construct a simple square
2. Draw a line from the midpoint of one side of the square to an opposite corner
3. Use that line as the radius to draw an arc that defines the height of the rectangle
4. Complete the golden rectangle
Golden Spiral
In geometry, a golden spiral is a logarithmic spiral whose growth factor b is related to j, the golden ratio. Specifically, a golden spiral gets wider (or further from its origin) by a factor of j for every quarter turn it makes.
Successive points dividing a golden rectangle into squares lie on
a logarithmic spiral which is sometimes known as the golden spiral.
Image Source: http://mathworld.wolfram.com/GoldenRatio.html
Proportion - Golden Ratio and Rule of Thirds
Proportion refers the size relationship of visual elements to each other and to the whole picture. One of the reasons proportion is often considered important in composition is that viewers respond to it emotionally. Proportion in art has been examined for hundreds of years, long before photography was invented. One proportion that is often cited as occurring frequently in design is the Golden mean or Golden ratio.
Golden Ratio: 1, 1, 2, 3, 5, 8, 13, 21, 34 etc. Each succeeding number after 1 is equal to the sum of the two preceding numbers. The Ratio formed 1:1.618 is called the golden mean - the ratio of bc to ab is the same as ab to ac. If you divide each smaller window again with the same ratio and joing their corners you end up with a logarithmic spiral. This spiral is a motif found frequently throughout nature in shells, horns and flowers (and my Science & Art logo).
The Golden Mean or Phi occurs frequently in nature and it may be that humans are genetically programmed to recognize the ratio as being pleasing. Studies of top fashion models revealed that their faces have an abundance of the 1.618 ratio.
Tlc.discovery.com/convergence/humanface/articles/mask.html
Many photographers and artists are aware of the rule of thirds, where a picture is divided into three sections vertically and horizontally and lines and points of intersection represent places to position important visual elements. The golden ratio and its application are similar although the golden ratio is not as well known and its' points of intersection are closer together. Moving a horizon in a landscape to the position of one third is often more effective than placing it in the middle, but it could also be placed near the bottom one quarter or sixth. There is nothing obligatory about applying the rule of thirds. In placing visual elements for effective composition, one must assess many factors including color, dominance, size and balance together with proportion. Often a certain amount of imbalance or tension can make an image more effective. This is where we come to the artists' intuition and feelings about their subject. Each of us is unique and we should strive to preserve those feelings and impressions about our chosen subject that are different.
Golden mean grid applied a simple composition
On analyzing some of my favorite photographs by laying down grids (thirds or golden ratio in Adobe Photoshop) I find that some of my images do indeed seem to correspond to the rule of thirds and to a lesser extent the golden ratio, however many do not. I suspect an analysis of other photographers' images would have similar results. There are a few web sites and references to scientific studies that have studied proportion in art and photography but I have not come across any systematic studies that quantified their results- maybe I just need to look harder (see link for more information about the use of the golden ratio: http://photoinf.com/Golden_Mean/).
In summary, proportion is an element of design you should always be aware of but you must also realize that other design factors along with your own unique sensitivity about the subject dictates where you should place items in the viewfinder. Understanding proportion and various elements of design are guidelines only and you should always follow your instincts combined with your knowledge. Never be afraid to experiment and try something drastically different, and learn from both your successes and failures. Also try to be open minded about new ways of taking pictures, new techniques, ideas - surround yourself with others that share an open mind and enthusiasm and you will improve your compositional skills quickly.
35 mm film has the dimensions 36 mm by 24 mm (3:2 ratio) - golden mean ration of 1.6 to 1 Points of intersection are recommended as places to position important elements in your picture.
Golden Ratio in Nature
Adolf Zeising, whose main interests were mathematics and philosophy, found the golden ratio expressed in the arrangement of branches along the stems of plants and of veins in leaves. He extended his research to the skeletons of animals and the branchings of their veins and nerves, to the proportions of chemical compounds and the geometry of crystals, even to the use of proportion in artistic endeavors. In these phenomena he saw the golden ratio operating as a universal law.[38] Zeising wrote in 1854:
The Golden Ratio is a universal law in which is contained the ground-principle of all formative striving for beauty and completeness in the realms of both nature and art, and which permeates, as a paramount spiritual ideal, all structures, forms and proportions, whether cosmic or individual, organic or inorganic, acoustic or optical; which finds its fullest realization, however, in the human form.
Source: http://www.xgoldensection.com/xgoldensection.html
Source:: http://www.goldennumber.net/hand.htm
A slice through a Nautilus shell reveals golden spiral construction principle.
The effectiveness of the Golden Mean
The explanation which follows is very succinct. For a much more detailed explanation, with very interesting animations, see the web site in the reference.
In many cases, the head of a flower is made up of small seeds which are produced at the centre, and then migrate towards the outside to fill eventually all the space (as for the sunflower but on a much smaller level). Each new seed appears at a certain angle in relation to the preceeding one. For example, if the angle is 90 degrees, that is 1/4 of a turn, the result after several generations is that represented by figure 1.
Of course, this is not the most efficient way of filling space. In fact, if the angle between the appearance of each seed is a portion of a turn which corresponds to a simple fraction, 1/3, 1/4, 3/4, 2/5, 3/7, etc (that is a simple rational number), one always obtains a series of straight lines. If one wants to avoid this rectilinear pattern, it is necessary to choose a portion of the circle which is an irrational number (or a nonsimple fraction). If this latter is well approximated by a simple fraction, one obtains a series of curved lines (spiral arms) which even then do not fill out the space perfectly (figure 2).
In order to optimize the filling, it is necessary to choose the most irrational number there is, that is to say, the one the least well approximated by a fraction. This number is exactly the golden mean. The corresponding angle, the golden angle, is 137.5 degrees. (It is obtained by multiplying the non-whole part of the golden mean by 360 degrees and, since one obtains an angle greater than 180 degrees, by taking its complement). With this angle, one obtains the optimal filling, that is, the same spacing between all the seeds (figure 3).
This angle has to be chosen very precisely: variations of 1/10 of a degree destroy completely the optimization. (In fig 2, the angle is 137.6 degrees!) When the angle is exactly the golden mean, and only this one, two families of spirals (one in each direction) are then visible: their numbers correspond to the numerator and denominator of one of the fractions which approximates the golden mean : 2/3, 3/5, 5/8, 8/13, 13/21, etc.
These numbers are precisely those of the Fibonacci sequence (the bigger the numbers, the better the approximation) and the choice of the fraction depends on the time laps between the appearance of each of the seeds at the center of the flower.
This is why the number of spirals in the centers of sunflowers, and in the centers of flowers in general, correspond to a Fibonacci number. Moreover, generally the petals of flowers are formed at the extremity of one of the families of spiral. This then is also why the number of petals corresponds on average to a Fibonacci number.
Golden Ratio in Architecture and Art
Many architects and artists have proportioned their works to approximate the golden ratio—especially in the form of the golden rectangle, in which the ratio of the longer side to the shorter is the golden ratio—believing this proportion to be aesthetically pleasing. [Source: Wikipedia.org]
Here are few examples:
Parthenon, Acropolis, Athens. This ancient temple fits almost precisely into a golden rectangle.
Source: http://britton.disted.camosun.bc.ca/goldslide/jbgoldslide.htm
The Vetruvian Man"(The Man in Action)" by Leonardo Da Vinci .We can draw many lines of the rectangles into this figure. Then, there are three distinct sets of Golden Rectangles: Each one set for the head area, the torso, and the legs.
Leonardo's Vetruvian Man is sometimes confused with principles of "golden rectangle", however that is not the case. The construction of Vetruvian Man is based on drawing a circle with its diameter equal to diagonal of the square, moving it up so it would touch the base of the square and drawing the final circle between the base of the square and the mid-point between square's center and center of the moved circle.
Source : www.world-mysteries.com
Geometry in Nature
Voronoi Diagram ( continued)
Voronoi in nature
Voronoi pattern/ tessellation is significant in the skin of different species in nature. Examples are given below:
Giraffe
Has nature created Voronoi Diagrams on these beautiful animals ?
Are they hiding something more ?
Is there any symmetry in shape and size of polygons ?
Is the number of polygons constant on each Giraffe ?
(Source: www.mcs.anl.gov/~csverma/Misc.html)
Turtle exoskeleton ( Source: http://www.desertgold.com/park/pics/turtle.jpg)
Voronoi fractals in plants ( Source: http://www.flickr.com/photos/flight404/538133104/)
"Reticulum Plasmatique." Fig. 321. From On Growth and Form.
D'Arcy Thompson.
Alligator skin_ voronoi tessellation ( Source: tosca.cs.technion.ac.il/book/slides/Stanford0)
Skin of a tiger _ voronoi tessellation (Source: tosca.cs.technion.ac.il/book/slides/Stanford0)
Application of Voronoi diagram in different fields
A. Social & planning aspects
There are a wide variety of applications of Voronoi diagrams. They are more important then what one might come to believe. Some of the applications are as follows:
1. Nearest Neighbour Search: This is the most obvious application of Voronoi Diagrams.
2. Facility Location: The example that is often quoted in this case is the example of choosing where to place a new Antenna in case of cellular mobile systems and similarly deciding the location of a new McDonalds given a number of them already exist in the city.
3. Path Planning: Suppose one models the sites as obstacles, then they can be used to determine the best path (a path that stays at a maximum distance from all obstacles or sites).
There are a number of other applications, such as in Geophysics, Metrology, Computer Graphics, Epidemiology and even pattern recognition. A very good example that illustrates how they can be used was the analysis of the Cholera epidemic in London in 1854, in which physician John Snow determined a very strong correlation of deaths with proximity to a particular infected pump (specific example from Wolfram Mathworld).
Let’s consider the specific example of path planning . Consider a robot placed in one corner of a room with stuff dispersed around.
Image Source:
tosca.cs.technion.ac.il/book/slides/Stanford0
Now the best path from the point where the robot is located to the goal would be the one in which the robot is farthest from the nearest obstacle at any point in time. To find such a path, the Voronoi diagram of the room would be required to be found out. Once it is done, the vertices or the skeleton of the Voronoi Diagram provides the best path. Which path ultimately is to be taken can be found out by comparing the various options (alternative paths) by using search algorithms.
Image Source:
tosca.cs.technion.ac.il/book/slides/Stanford0
B) Polymer physics
The Voronoi diagram is useful in polymer physics. It can be used to represent free volume of the polymer.
C) Wireless network
It is also used in derivations of the capacity of a wireless network.Voronoi graphs are a promising approach to create easy, but realistic movement models for nodes of a mobile network. Artificial scenarios with streets, sidewalks and buildings can thus be calculated and simulated.
Image Source:
www.lkn.ei.tum.de/~hmz/research.html?lang=en
D) Climatology
in climatology, Voronoi diagrams are used to calculate the rainfall of an area, based on a series of point measurements. In this usage, they are generally referred to as Thiessen polygons.
Image Source:
www-personal.umich.edu/.../win01/sarhaus
Bisectors, buffers, and proximity zones (Thiessen polygons)
E) Growth pattern of forest
Voronoi diagrams are used to study the growth patterns of forests and forest canopies, and may also be helpful in developing predictive models for forest fires.
F) Computer graphics
Voronoi diagrams are also used in computer graphics to procedurally generate some kinds of organic looking textures.
Image Source:
tosca.cs.technion.ac.il/book/slides/Stanford0
Golan Levin’s experiments in using Voronoi diagrams to obtain aesthetic forms yielded probably even more pleasant results. The ones below give a very delicate look to their subjects.
image Source:
http://www.flong.com/projects/zoo/
The tilings that are produced by just mild tweaks to the basic definition of a Voronoi Diagram for a 2-D case that I had talked about earlier can give rise to a variety of tilings. Say like the one below:
Image Source:
http://www.cgl.uwaterloo.ca/~csk/papers/kaplan_isama1999.pd
G) Fractals from voronoi
To create a fractal, first create a Voronoi diagram from some points, next add more points and then create the Voronoi diagrams inside individual Voronoi Regions. Some sample progression could be like this:
Image Source:
http://www.righto.com/fractals/vor.html
Repeating the above process recursively on the above would give the following Voronoi fractal.
Image Source:
http://www.righto.com/fractals/vor.html
Interestingly, this fractal looks like the structure of a leaf. The above was repeated in color by Frederik Vanhoutte to get some spectacular results.
Image Source:
onionesquereality.wordpress.com/.../voronoi-art/
H) Robot navigation
In autonomous robot navigation, Voronoi diagrams are used to find clear routes. If the points are obstacles, then the edges of the graph will be the routes furthest from obstacles (and theoretically any collisions).
I) Computational chemistry
In computational chemistry, Voronoi cells defined by the positions of the nuclei in a molecule are used to compute atomic charges. This is done using the Voronoi deformation density method.
voronoi in architecture
a) Voronoi bookshelf by Marc Newson
The Voronoi Bookshelf by Marc Newson is made from a single slab of white carrara marble. The organic shape gives the eye a welcome break from the monotony of rectangular shelving. Owning a unit like this would force you to look at your personal objects in a whole new way as you hunted for the right alcove in which to put them. This is a fantastic piece of design that will no doubt have lasting appeal. I have no idea how this would make it into the average home, but perhaps Newson liked the irony of using a totally impractical material for such a banal piece of household furniture. A shelving unit turned into glorious sculpture! I would not be surprised if it is reproduced in a more practical material in the future.
b) Melbourne Federation Square - Lab Architecture
Type:
Public Square and cultural and commercial buildings.
Construction years:
Winner announced:1999
Date started: 2000
Date opened: Saturday 26 October 2002
Location:
Flinders Street, Melbourne, Victoria, Australia
Top view
Facade/ fractal/ voronoi system
Source:
www.pushpullbar.com/forums/australia/7203-mel
Inside
c) Study by Object e-architecture
Brief: This is a first attempt to use the voronoi diagrams for a specific design. The initial set of points is defined by the program requirements. The edges of the voronoi cells become the structure, while a first idea for enclosed space was to use again the voronoi cells (in a 'smoothed' version) as clusters of space in a configuration that resembles the relation of bones to organs. This project though was not developed further...
For more information about computing convex hulls, voronoi diagrams, and other triangulations, check out the qhull website. Qhull is used in Matlab and many other computational geometry applications.
Source: object-e.blogspot.com
d) Voronoi by D.FILTER 2.0
Warsaw Museum of Modern Art [competition entry]
e) Analysis by MatSys (evolution of “Material Systems”)
Established in 2004 by Andrew Kudless, Matsys is an architectural design studio that explores the emergent relationships between architecture, engineering, biology, and computation. Based on the idea that architecture can be understood as a material body with its own intrinsic and extrinsic forces relating to form, growth, and behavior, the studio investigates methodologies of performative integration through geometric and material differentiation. The studio’s work ranges from speculative and built projects to the crafting of new tools which facilitate an interdisciplinary approach to the design and fabrication of architecture.
2005-2006
Voronoi Morphologies is the latest development in an ongoing area of research into cellular aggregate structures. The voronoi algorithm is used in a wide range of fields including satellite navigation, animal habitat mapping, and urban planning as it can easily adapt to local contingent conditions. Within our research, it is used as a tool to facilitate the translation and materialization of data from particle-simulations and other point-based data into volumetric form. Through this process, it becomes much easier to produce highly differentiated structures that are responsive to local performance criteria.
The project was developed though both 2D and 3D voronoi cellular structures. In both cases, a field of points is used to determine regions of space, or cells, that are closer to a certain point than any other point. As the cells are not constrained by a fixed geometric topology, the cells properties can be tuned in much more specific ways than a tradition rectangular or hexagonal cell arrangement. A custom-designed script was written to connect Rhino with Qhull which did the actual voronoi calculations. The script also digitally unfolds, labels, and prepares the geometry for CNC fabrication.
This technique was developed in collaboration with Jelle Feringa of EZCT Architecture and Design Research in Paris.
Source: www.materialsystems.org
Voronoi in nature
Voronoi pattern/ tessellation is significant in the skin of different species in nature. Examples are given below:
Giraffe
Has nature created Voronoi Diagrams on these beautiful animals ?
Are they hiding something more ?
Is there any symmetry in shape and size of polygons ?
Is the number of polygons constant on each Giraffe ?
(Source: www.mcs.anl.gov/~csverma/Misc.html)
Turtle exoskeleton ( Source: http://www.desertgold.com/park/pics/turtle.jpg)
Voronoi fractals in plants ( Source: http://www.flickr.com/photos/flight404/538133104/)
"Reticulum Plasmatique." Fig. 321. From On Growth and Form.
D'Arcy Thompson.
Alligator skin_ voronoi tessellation ( Source: tosca.cs.technion.ac.il/book/slides/Stanford0)
Skin of a tiger _ voronoi tessellation (Source: tosca.cs.technion.ac.il/book/slides/Stanford0)
Application of Voronoi diagram in different fields
A. Social & planning aspects
There are a wide variety of applications of Voronoi diagrams. They are more important then what one might come to believe. Some of the applications are as follows:
1. Nearest Neighbour Search: This is the most obvious application of Voronoi Diagrams.
2. Facility Location: The example that is often quoted in this case is the example of choosing where to place a new Antenna in case of cellular mobile systems and similarly deciding the location of a new McDonalds given a number of them already exist in the city.
3. Path Planning: Suppose one models the sites as obstacles, then they can be used to determine the best path (a path that stays at a maximum distance from all obstacles or sites).
There are a number of other applications, such as in Geophysics, Metrology, Computer Graphics, Epidemiology and even pattern recognition. A very good example that illustrates how they can be used was the analysis of the Cholera epidemic in London in 1854, in which physician John Snow determined a very strong correlation of deaths with proximity to a particular infected pump (specific example from Wolfram Mathworld).
Let’s consider the specific example of path planning . Consider a robot placed in one corner of a room with stuff dispersed around.
Image Source:
tosca.cs.technion.ac.il/book/slides/Stanford0
Now the best path from the point where the robot is located to the goal would be the one in which the robot is farthest from the nearest obstacle at any point in time. To find such a path, the Voronoi diagram of the room would be required to be found out. Once it is done, the vertices or the skeleton of the Voronoi Diagram provides the best path. Which path ultimately is to be taken can be found out by comparing the various options (alternative paths) by using search algorithms.
Image Source:
tosca.cs.technion.ac.il/book/slides/Stanford0
B) Polymer physics
The Voronoi diagram is useful in polymer physics. It can be used to represent free volume of the polymer.
C) Wireless network
It is also used in derivations of the capacity of a wireless network.Voronoi graphs are a promising approach to create easy, but realistic movement models for nodes of a mobile network. Artificial scenarios with streets, sidewalks and buildings can thus be calculated and simulated.
Image Source:
www.lkn.ei.tum.de/~hmz/research.html?lang=en
D) Climatology
in climatology, Voronoi diagrams are used to calculate the rainfall of an area, based on a series of point measurements. In this usage, they are generally referred to as Thiessen polygons.
Image Source:
www-personal.umich.edu/.../win01/sarhaus
Bisectors, buffers, and proximity zones (Thiessen polygons)
E) Growth pattern of forest
Voronoi diagrams are used to study the growth patterns of forests and forest canopies, and may also be helpful in developing predictive models for forest fires.
F) Computer graphics
Voronoi diagrams are also used in computer graphics to procedurally generate some kinds of organic looking textures.
Image Source:
tosca.cs.technion.ac.il/book/slides/Stanford0
Golan Levin’s experiments in using Voronoi diagrams to obtain aesthetic forms yielded probably even more pleasant results. The ones below give a very delicate look to their subjects.
image Source:
http://www.flong.com/projects/zoo/
The tilings that are produced by just mild tweaks to the basic definition of a Voronoi Diagram for a 2-D case that I had talked about earlier can give rise to a variety of tilings. Say like the one below:
Image Source:
http://www.cgl.uwaterloo.ca/~csk/papers/kaplan_isama1999.pd
G) Fractals from voronoi
To create a fractal, first create a Voronoi diagram from some points, next add more points and then create the Voronoi diagrams inside individual Voronoi Regions. Some sample progression could be like this:
Image Source:
http://www.righto.com/fractals/vor.html
Repeating the above process recursively on the above would give the following Voronoi fractal.
Image Source:
http://www.righto.com/fractals/vor.html
Interestingly, this fractal looks like the structure of a leaf. The above was repeated in color by Frederik Vanhoutte to get some spectacular results.
Image Source:
onionesquereality.wordpress.com/.../voronoi-art/
H) Robot navigation
In autonomous robot navigation, Voronoi diagrams are used to find clear routes. If the points are obstacles, then the edges of the graph will be the routes furthest from obstacles (and theoretically any collisions).
I) Computational chemistry
In computational chemistry, Voronoi cells defined by the positions of the nuclei in a molecule are used to compute atomic charges. This is done using the Voronoi deformation density method.
voronoi in architecture
a) Voronoi bookshelf by Marc Newson
The Voronoi Bookshelf by Marc Newson is made from a single slab of white carrara marble. The organic shape gives the eye a welcome break from the monotony of rectangular shelving. Owning a unit like this would force you to look at your personal objects in a whole new way as you hunted for the right alcove in which to put them. This is a fantastic piece of design that will no doubt have lasting appeal. I have no idea how this would make it into the average home, but perhaps Newson liked the irony of using a totally impractical material for such a banal piece of household furniture. A shelving unit turned into glorious sculpture! I would not be surprised if it is reproduced in a more practical material in the future.
b) Melbourne Federation Square - Lab Architecture
Type:
Public Square and cultural and commercial buildings.
Construction years:
Winner announced:1999
Date started: 2000
Date opened: Saturday 26 October 2002
Location:
Flinders Street, Melbourne, Victoria, Australia
Top view
Facade/ fractal/ voronoi system
Source:
www.pushpullbar.com/forums/australia/7203-mel
Inside
c) Study by Object e-architecture
Brief: This is a first attempt to use the voronoi diagrams for a specific design. The initial set of points is defined by the program requirements. The edges of the voronoi cells become the structure, while a first idea for enclosed space was to use again the voronoi cells (in a 'smoothed' version) as clusters of space in a configuration that resembles the relation of bones to organs. This project though was not developed further...
For more information about computing convex hulls, voronoi diagrams, and other triangulations, check out the qhull website. Qhull is used in Matlab and many other computational geometry applications.
Source: object-e.blogspot.com
d) Voronoi by D.FILTER 2.0
Warsaw Museum of Modern Art [competition entry]
e) Analysis by MatSys (evolution of “Material Systems”)
Established in 2004 by Andrew Kudless, Matsys is an architectural design studio that explores the emergent relationships between architecture, engineering, biology, and computation. Based on the idea that architecture can be understood as a material body with its own intrinsic and extrinsic forces relating to form, growth, and behavior, the studio investigates methodologies of performative integration through geometric and material differentiation. The studio’s work ranges from speculative and built projects to the crafting of new tools which facilitate an interdisciplinary approach to the design and fabrication of architecture.
2005-2006
Voronoi Morphologies is the latest development in an ongoing area of research into cellular aggregate structures. The voronoi algorithm is used in a wide range of fields including satellite navigation, animal habitat mapping, and urban planning as it can easily adapt to local contingent conditions. Within our research, it is used as a tool to facilitate the translation and materialization of data from particle-simulations and other point-based data into volumetric form. Through this process, it becomes much easier to produce highly differentiated structures that are responsive to local performance criteria.
The project was developed though both 2D and 3D voronoi cellular structures. In both cases, a field of points is used to determine regions of space, or cells, that are closer to a certain point than any other point. As the cells are not constrained by a fixed geometric topology, the cells properties can be tuned in much more specific ways than a tradition rectangular or hexagonal cell arrangement. A custom-designed script was written to connect Rhino with Qhull which did the actual voronoi calculations. The script also digitally unfolds, labels, and prepares the geometry for CNC fabrication.
This technique was developed in collaboration with Jelle Feringa of EZCT Architecture and Design Research in Paris.
Source: www.materialsystems.org
Subscribe to:
Posts (Atom)