256b explanation

Wold is a generative sonic universe in which players collaboratively explore solar systems and planets while growing and playing sound-trees.

220b explanation

Wold is an interface for gestural control of granular synthesis, using physical associations and visual feedback to make the large parameter space more intuitive.


Wold is an application for the simultaneous exploration of a virtual environment and of the properties and textures of sounds. In it, you navigate through a solar system which contains a number of planets.

From the default view of the entire solar system, you can zoom in on each of these planets, all the way down to a small slice of the planet's surface. Once you have chosen and zoomed in on a single planet, you can hold various numbers of fingers down on the screen to grow various types of fantastical trees.

As those trees grow, they make strange sounds. Once you lift your fingers, the sound will fade. But if you then start to rub and swipe your fingers around through the leaves of the trees, they will start to make sound again, as well as swinging back and forth in an invisible wind generated by your finger movements. As the leaves on the trees move around, so does the sound produced by the tree morph and change.

How's it work?

The trees are generated using Lindenmayer systems, which is a type of generative grammar often used to visualize complex fractal systems and simulate botanical lifeforms. The swiping/wind motion works by modifying the angles of the nodes in the grammar/tree which represent rotations. The magnitude of this modification is proportional to the horizontal velocity of the finger motion.

The systems in this case are doing double duty as both tree generators and parameters to an underlying granular synthesis engine. The x/y position of each leaf in each tree represents a pair of parameters being passed to a single grain of sound which repeats while stochastically varying itself each time around that leaf's position in parameter-space. The X position of the leaves represent the portion of the underlying sample which they should create themselves from, and the Y position represents density/grain length (which are correlated in this system).

Why's it cool?

By linking up a granular synth to these manually modifiable generative systems, Wold creates the potential for exploring sounds on a micro-timescale while hiding much of the complexity behind its simple interface. If you swipe a tree to the left, you'll hear a sonic texture which is generated from the very beginning of an underlying sample, whereas a tree swept to the right will extract sounds toward the end of the sample.

Also, the entire universe of Wold is a shared space, so that each planet can be simultaneously explored and modified by multiple players, and they will each see each other's changes. This allows for the creation of personal environments as well as cooperative play.

What's next?

The next steps for Wold are:




You should simply be able to open the XCode project and immediately build and run the binary on an iPad. It's only been tested on an iPad 2, so there might be some performance issues on the iPad 1. It won't run on the simulator.