Special effects in movies have always had a problem: water drops are a consistent size. The one thing that always tips a viewer off in old movies are water drops that look huge next to scaled models.

It hasn't improved much in the last 50 years. Water looks fake and beer is even harder because of the bubbles but computer animation is a $55 billion global industry so it's only a matter of time before someone meets the challenge. A group of scientists think they have done it.

“As you pour beer into a glass, you see bubbles appearing on what are called nucleation sites, where the glass isn’t quite smooth,” CSIRO fluids researcher Dr Mahesh Prakash says.

A frame from a computer-generated animation showing a beer being poured into a stein. Credit: CSIRO

“The bubbles expand to a certain size then rise up in streams to the surface, where they bump into each other and form a raft of foam that floats on the top.”

Dr. Prakash and his colleagues have captured the maths describing these processes in software that allows movie makers, film production houses and others to create super-realistic special effects.

The four-year project is being undertaken jointly by CSIRO and South Korea’s Electronics and Telecommunications Research Institute, one of the world’s largest computer graphics developers for games, with most of the research being done in Melbourne.

New fluids animation. Convincing enough? Credit: CSIRO

Clever maths called smoothed particle hydrodynamics (SPH) helps the software do its job by working smarter not harder. The software uses less computer power and takes less time to get better results than other special effects software it has been benchmarked against.

CSIRO Business and Commercialisation Manager, Andrew Dingjan says CSIRO and ETRI hope this will bring the fluid animation software within reach of smaller film production houses.

“Big Hollywood studios spend vast sums on single-use solutions when they make blockbusters like ‘Poseidon’ and ‘The Perfect Storm’ but we’d like our software to make realistic special effects easier to come by,” Mr Dingian says.

Source: CSIRO Australia