How I Used Space Colonisation to Build an Alien Planet

Lucas Milner

In 2019 QUT invited me as a technical artist to help them build what would seem to me as an alien planet — full of strange and wildly variant fungi or plant-like organisms I had never seen.

Picture of The Living Reef at QUT by Real-time Artist, Ryan Bargiel.
Picture of The Living Reef at QUT by Real-time Artist, Ryan Bargiel.
The Living Reef. Image by QUT real-time artist Ryan Bargiel.

The Living Reef is an immersive and interactive 3D underwater ecosystem with complex artificial intelligence (AI) driving marine species to behave as they would in the ocean, and coral ‘grown’ using special algorithms that replicate what happens in nature.

With developers at The Cube Studio and QUT researchers including reef experts Brett Lewis and Luke Nothdurft we created 11 coral types, and 20 different fish species and other marine life ‘living’ through the 10-metre tall screens — numbering about 10,000 in total.

The secret to this success was in the ‘space colonisation algorithm’ and discovering it took me into the best rabbit hole around — YouTube.

YouTube gave me my ‘Ah-ha!’ moment

My ‘Ah-ha!’ moment came when I found technical examples by Kevin McNamara who is now CEO for an autonomous data generation company in Palo Alto but in a previous life (2011) made coral generation samples which I guessed were used for Finding Dory (2016), the Finding Nemo sequel.

He simulated coral growth in the 3D animation software, Houdini, using the space colonisation algorithm — first used to model leaf vein and tree branch patterns by simulating the competition for space between those growing elements.

Leaf venation Credit:
Simulating crowds based on a space colonisation algorithm. Credit: A.L. Bicho via YouTube.

So, if I felt like a coral landscape was like an alien planet why shouldn’t space colonisation be the answer to my programming problem? Kevin’s examples had inspired me to learn more about the space colonisation algorithm and in doing so I discovered I had used it in my own past.

Space colonisation

Machine world in The Matrix Revolutions. Courtesy of Roadshow Films.

Space colonisation algorithms have actually been used in several applications. These have also been also used to simulate crowds, mimic collision avoidance, crowd density relationships and to model crowd control. In the realm of visual effects, it could simulate inter-connected ecosystems to create environments like the machine world in The Matrix.

Building the Reef

Variations in the availability of ‘food’ and the search radius effect on space colonisation.

Traditionally when programmers modelled an object which conformed to a given dimension or volume, they would manually create and move the model vertices and polygons to satisfy one single outcome within a space.

That was done visually — not mathematically — because 3D objects did not collide with each other the way real-world objects collided. And, while it manually achieved the same outcome as a space colonisation algorithm, this process was slower and less accurate.

By randomising certain properties using the space colonisation algorithm, objects could (and did) vary wildly. The model performed in a much more organic way and, ultimately, I produced an end product more quickly and faithfully, and with an element of surprise.

Coral reefs — the alien planet


I considered the classic L-System where code could iterate over a rule and create really organic results in branching trees.

Inspiring generation reference. Credit: Kevin McNamara via YouTube

I also tried parametric modelling — often referred to as biomimicry — which provided a simple model deformation like a bend or twist which, but when repeated across many objects made the underlying rhythm became very complex.

I added random values for variation, but my production generation experiments proved the parametric workflow was difficult to control.

It can be a showstopper in a production environment if you are not prepared for a direction that simultaneously commands growth in an area that cannot have growth.

Initial coral meshes imported into the Unity engine.
Pillar coral variants created by moving the ‘food’ away from the coral, making it ‘reach’.

How coral grows depends on such things as how much space it has, how it competes for that space, and the amount of food it can access.

My earlier processes blindly followed a directive whereas the space colonisation algorithm would start with a validity step like a set volume or amount of food to act upon.

So, we set those parameters, along with others, within the space colonisation algorithms, and generated coral of varying types and ages.

Using the algorithms, we were able to create unique pieces of coral within seconds. Digital artists could then add colour and place them throughout the reef scene.

Various bulbous growths I generated with various procedural techniques.


Within the digital environment, we let them go and they behave the way they would in nature within their rules, but without set paths. In a way, each fish was ‘thinking’ for itself.

Human interaction

Mini-games in The Living Reef have been a big hit and there are plans to add more activities in the future, I am researching how to allow interaction with the Space Colonisation Algorithm which will expose options for editing the availability of food, show how 2 corals compete for resources within the algorithm and also introduce obstacles that the coral will need to grow around.

Audience reviews

It was the highlight of the 2019–20 QUT Summer Holiday Program at The Cube after launching on January 11th and will continue to screen throughout the year as we develop new elements.

If, like me, you are inclined to stalk developers for programming tips, here is a list of a few recommended reads:

Allan Bishop’s blog post on ‘The Living Reef’ which focuses on simulating over 700 AI-controlled fish —

Ryan Bargiel’s ArtStation where he shares a close-up look into how much attention the different species of fish and their environments were given:

I mentioned Zaha Hadid’s parametric design applying biomimicry in architecture. Some samples:

For technical artists, I demonstrated coral creation and the interoperability of 3ds Max® and Side FX using the Houdini engine and research into runtime Houdini engine access within Unity.

About Lucas Milner

The Cube is housed in QUT’s Science and Engineering Centre and consists of 48 multi-touch screens across two storeys.

Collaborating with QUT researchers and drawing on knowledge and data from research areas in Science, Technology, Engineering and Mathematics (STEM), The Cube facilitates opportunities for the public to discover, visualise and contribute to research projects.


Learning and Big Solutions (LABS) from QUT Science and Engineering Faculty

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Science, technology, engineering & mathematics (STEM) news, research, insights and events from QUT Science and Engineering Faculty. #qutstem



Learning and Big Solutions (LABS) from QUT Science and Engineering Faculty

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