If you're attending SIGGRAPH 2007 next week in San Diego, don't miss a demonstration done by Australian and South Korean researchers. They will pour virtual beer during the conference. They say that 'the physics of bubble creation in carbonated drinks like beer is complex,' but add that their fluid special effects software was able to capture this complexity. Moreover, through what they call smoothed particle hydrodynamics (SPH), their software 'uses less computer power and takes less time to get better results than other special effects software it has been benchmarked against.' Now the researchers want to sell their approach to Hollywood studios.
The illustration above describes such a "simulation of pouring of ale and stout into a beer mug: images on the top show realistic rendered images of ale and the bottom images indicate realistic rendered images of stout (Credit: CSIRO, Australia and ETRI, South Korea).
This software has been primarily developed in Melbourne, Australia, at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), in a collaboration with South Korea's Electronics and Telecommunications Research Institute (ETRI).
And don't think that modeling a beer being poured in a mug is easy. "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 Mahesh Prakash says. "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."
And you can find other examples of realistic fluid special effects in 3D on the CSIRO website, which gives the following explanation. "The animation and rendering of fluids is a challenging problem in computer graphics. To achieve photorealism in the animation of fluids, a branch of maths called computational fluid dynamics is increasingly being used. CSIRO mathematicians are world leaders in this research. Bubbles growing and shrinking and floating to the top of a glass of beer, water washing around buildings in a flooded street, two liquids mixing together, and smoke wafting through the air – all these can be described by mathematical equations. These equations are called smooth particle hydrodynamics algorithms (SPH).
From this page, you'll be able to watch a short video demonstrating the software's capability, with 3 kinds of events: waves lapping on the shore; beer pouring into a stein -- or mug; and water flooding a street.
The researchers will present their work on August 9 at SIGGRAPH 2007 in a session about Fluids. The title of their presentation is titled "Bubbling and Frothing Liquids" with a subtitle of "A method to generate bubbles from gas contained in liquids and simulate their dynamic behavior using a particle-based fluid simulation technique."
Their paper is published in the collection of the ACM SIGGRAPH 2007 papers (Volume 26, Issue 3, Article No. 97, July 2007). From this link, you'll have access to the abstract. "We present a discrete particle based method capable of creating very realistic animations of bubbles in fluids. It allows for the generation (nucleation) of bubbles from gas dissolved in the fluid, the motion of the discrete bubbles including bubble collisions and drag interactions with the liquid which could be undergoing complex free surface motion, the formation and motion of coupled foams and the final dissipation of bubbles. This allows comprehensive simulations of dynamic bubble behavior. [...] The method is used here to realistically animate the pouring of a glass of beer, starting with a stream of fresh beer entering the glass, the formation of a dense cloud of bubbles, which rise to create a good head as the beer reaches the top of the glass."
You'll also be able to read the full paper (PDF format, 6 pages, 2.53 MB), from which the above illustration has been extracted.
Mark Hachman delivers the perfect conclusion for Gearlog in "Want a Virtual Beer? Wait Until Next Week" (August 3, 2007). "Mmmm... virtual beer... [...] While it's technically impressive, we're sure you have the same reaction: why the need for CGI beer, anyway?"
Sources: CSIRO news release, August 3, 2007; and various websites
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