News and events - Tampere University of Technology

Fluid simulation makes water flow more realistically in computer games

In his dissertation, Master of Science (Technology) Timo Kellomäki studied quickly applied methods that enable simulating vast water masses using the calculation methods available in computer games. Result: more believable hydro experiences.

Visually, computer games have achieved a highly realistic level. The virtual game worlds are typically very static and unchanging, however, and there are few ways for the player to affect the world. Water, in particular, is a highly problematic element. In order to enable credible interaction with water, real-time simulation is required, which is typically too heavy a process for existing game equipment.

“Fortunately, the properties of water do not have to be equally realistic in the game context as when designing actual dams and bridges. It is surprising, really, how rough a simplification produces an outcome that is credible enough. By knowing which aspects to simplify, it is possible to reduce the required calculation capacity to a sufficient extent,” Kellomäki explains.

In his dissertation, Kellomäki has developed new methods for making masses of water react to changing and moving barriers of different shapes in a credible manner. With his water simulation model, it is possible to dam up a river in a game, or change a river’s flow direction by dropping stones in the river bed. The results of the dissertation are already in play in the water simulation in the ‘Cities: Skylines’ hit game published by the Tampere-based Colossal Order game studio in March 2015.

Public defence of a doctoral dissertation on Friday, 4 December

MSc (Tech) Timo Kellomäki’s doctoral dissertation in the field of pervasive computing, ’Large-Scale Water Simulation in Games,’ will be publicly examined at the Faculty of Computing and Electrical Engineering of Tampere University of Technology (TUT) in lecture hall TB109 in the Tietotalo building (address: Korkeakoulunkatu 8, Tampere, Finland) on Friday, 4 December 2015 at 12 noon.

The opponents will be Assistant Professor Perttu Hämäläinen (Aalto University) and Professor Markku Turunen (University of Tampere). Professor Antti Valmari from the Department of Mathematics at TUT will act as the Chairman.

Timo Kellomäki (36) has completed his doctoral dissertation at the Department of Pervasive Computing at TUT. He now works as a generalist game programmer at Colossal Order.

The dissertation is available online at

Further information: Timo Kellomäki, tel. +358 (0) 45 354 8048,

News submitted by: Tiina Leivo
Keywords: science and research, water simulation, fluid simulation, computer games