3. Randomness


Topic

After the last class was about using external data for visualization, in this class we now deal with the topic of chance and probability.

From the 20th century onwards, in very different art movements, attempts have been made to find new forms of expression by including random operations.

In music, for example - in very free form - by John Cage and - guided by stochastic operations - by Iannis Xenakis.

Iannis Xenakis, N'Shima (1975)


John Cagem, Atlas Eclipticalis (1962)/p>

The trends of visual art that use the computer, that were already mentioned in the first units, also incorporate chance in various ways. Pioneers are Vera Molnar, Frieder Nake or Michael Noll.

On the other hand, ideas of Concrete Art can often be traced back to mathematical or statistical principles.


Random Walks

In his compositions Xenakis sometimes used "random walks", i.e. randomly controlled movements, which he printed and then laid a staff over the two-dimensional graph. This is how he arrived at tone durations and heights. The example "N'Shima" is composed in this way.
Here is a visualization of a graphic score of N'Shima:

Iannis Xenakis N'Shima

Iannis Xenakis, N'Shima, Random Walks of sectin 8. (Andreas Pirchner)



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Random functions and chance operations in P5

Random events are often controlled by creating random numbers. Their distribution can be controlled by a distribution function and their edges can be limited. This way, randomness can be channelled and steered in paths.

-> A random number can be generated in P5 with the function random().

-> RandomGaussian() can be used to generate random numbers that correspond to the Gaussian distribution (i.e. the "bell curve").https://p5js.org/reference/#/p5/randomGaussian

-> Particularly interesting is the use of Perlin Noise. Perlin Noise was developed by Ken Perlin for creating the CGI (Computer Generated Images) of the movie "Tron" and is one of the rare examples where a movie Oscar was awarded for an algorithm: https://en.wikipedia.org/wiki/Perlin_noise


Tutorials

Please watch this video playlist by Daniel Shiffman to understand the basics and reproduce the content:

Tutorials on Perlin Noise by Daniel Shiffman.


Assigment

Perlin Noise and Random Walks

Create a sketch in which an interesting structure is created by a random walk movement that is controlled by Perlin-Noise. Here is the coding challenge for it: Link