Dynamic Music & Sound in VESSEL by Kieran Lord

Alex J. Champandard on April 26, 2012

Curious about dynamic music & sound systems in games? The first few speakers of the Vienna Game/AI Conference 2012, taking place on September 18th and 19th, have been announced. Among them is Kieran Lord, who wrote an AI-driven system for fluid mixing of audio and a dynamic score in the indie hit VESSEL.

Tickets to this year's conference are now available here, and come with Early Bird Bonuses if you move fast to secure yours. Prices range from €96 to €192 only, with discounts for students.


VESSEL is an ambitious puzzle platformer set in a unique world where the player has tools to controls liquids. The entire game is very dynamic and open, and required an adaptive audio system to truly capture the fluid aspect of the game. The implementation is done using a control structure similar to a behavior tree, which dynamically decides what sections of the score to play.

About Kieran

Kieran Lord worked at Pandemic in Australia on DESTROY ALL HUMANS 2 and two un-announced AAA titles for consoles. He's since become an independent developer, not only building his own games and Unity plugins, but also becoming a core contributor on VESSEL.

Most notably, he worked on the dynamic sound/music system as well as gameplay and NPC artificial intelligence. Kieran is now a resident expert at the Labs in Austria.

Behind the Scenes

Q: What motivated you to write a dynamic music/sound system for VESSEL?

KL: There's two answers to that, need and ambition. We needed dynamic sound to go with the simulated fluid and physics. Static sounds in a realistically simulated world just feel 'wrong', and would have ruined the experience. As for the music… that was all about ambition. When we started talking about music it was just a question of how should we should make it dynamic, not if it should be dynamic or not. It turned out to be much harder than I had imagined but it adds a huge amount to the game.

Q: What was your most frustrating moment working on that part of VESSEL?

KL: This one's easy… we had one awful bug. No new sounds would play if the player walked past a certain area on one map of the game (the very first part of the factory). It drove us mad! In the end it turns out that it was a star crossed combination of level & sound design we had accidentally created the perfect conditions for a super-rare bug in the sound API. The joys of a fully dynamic system.

Q: What was your most rewarding moment in developing the dynamic sound/music system in vessel?

KL: Not so easy, we had lots of these. I think the biggest one for me was when we set up our first puzzle music test (using the system we went on to ship with). Playtesters actually didn't realise the music had changed most of the time… just that somehow they knew they were doing the right thing each time it did.

Q: Why did you decide to make a Unity plugin and what will it be able to do?

KL: There's two reasons… firstly, Vessel's music system was built specifically for Vessel… and we had so many great ideas when building the music for Vessel that just didn't fit with the game. And secondly, I missed the music when I had time to play with Unity again. Out of the box Unity can handle a looping audio clip in the background and after Vessel I just wasn't content with that anymore.

Find out more about the dynamic audio system behind VESSEL, how you can build your own and extend the concept at the Vienna Game/AI Conference 2012. Tickets are now available, and come with Early Bird bonuses if you move fast! Click here to secure your seat...

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