Computer Graphics World

August 2009 33 Fusion CI worked in concert with DMG, which did all the camera animations and renderings. DMG provided Stasiuk and his group with the geometry for all the forms that the water had to assume—a brain, a water bottle, a bridge, and a bunch of ba- nanas—which was done in Maxon's Cin- ema 4D. e Fusion CI team then used Autodesk's Maya to massage that geometry as the underlying shapes for the fluids. Fusion CI output the DMG animated shapes as OBJ files, then imported the in- formation into Maya, simplifying the data and using the modeling tools in Maya to ad- just the geometry so the simulations would run more efficiently. Next, the team output those results to the RealFlow format. e last step, and the most crucial one, involved applying the proprietary tools to drive the simulations within RealFlow. "Over the years we have amassed a big li- brary of all these tools that do all kinds of different fluid-effects phenomena. So when someone comes to us, we can usually think back and adapt something we have done before," explains Stasiuk. Because of this, Fusion CI can spend less time on R&D for a project than it would starting from scratch. For the Whole water commercial, the team spent about six weeks develop- ing the technology, and then another two weeks to run the sims and finish the job. In the application, the water had to look and behave like real water, but at the same time, it had to form sharply defined shapes with a lot of detail. And, the water had to hold the shapes so the viewer could iden- tify the form. "For example, the water had to form this very detailed brain shape, but at the same time, we had to maintain the il- lusion that it was water forming this thing. If you get all the particles to glom onto the shape and stick and stay, it looks like an ice sculpture. It starts to look like geometry." Using the earlier version of the tool, that's exactly what happened: e plug-in formed the shapes very clearly, Stasiuk says, but the substance didn't look like water anymore. It looked like an ice sculpture. e trick, he says, was to get the water to slosh around a bit while it formed the shapes, and then keep rippling, moving, and dripping. To this end, it had to have constant bits of wa- ter that dripped off. at extra water was generated with the rest of the water but would be allowed to drop off the shapes. "Having the water form a shape but still behave like water is sort of paradoxical," says Stasiuk. Finishing Up When Fusion CI was done with the simu- lation, it transferred the data to DMG in New Zealand via FTP, a process that took a few days in itself. "e data is huge," Sta- siuk says. While the end result is one long, continuous sim, the work actually entailed a number of versions of the simulations, each taking an average of three days to run on 64-bit Windows XP machines with eight cores and 16gb of RAM. Fusion CI created the data for each sim, establishing the particular behavior. e particle files were then meshed dur- ing a post process. e sim resulted in approximately 600,000 particles, while the mesh contained between three mil- lion and five million polygons, depend- ing on what was occurring in the shot. Fusion sent these meshes to DMG, to complete the commercial. Stasiuk's group compressed the 650 frames of data for each simulation down to 25gb, and then sent that via FTP to the visual effects facility—a process that took two days. After receipt, DMG imported the meshes into its Cinema 4D renderer. "DMG was great to work with," says Stasiuk. "ey gave us the time and cre- ative space we needed to make the fluids work, and had brilliant ideas on how to get the most out of the water. On top of that, their camera work and lighting made the water look fabulous." While the team at Fusion CI is no new- comer when it comes to fluid simulation, Stasiuk notes that this application was unique in a number of ways. He points out that the company is often asked to do ei- ther accent types or environmental types of fluid effects. He points out the differences: Accent effects are like characters having a fight, wherein the character splashes the other with a pan of oil, for instance, and his group does the oil as an accent add-in effect. An example of an environmental ef- fect would be a helicopter flying over an ocean, and that ocean is part of the back- ground's natural environment. "However, this was a highly art-direct- ed hero effect that was the entire visual for the entire commercial. It's not like it in- volved a little splash here or there behind a character," Stasiuk says. "It was the char- acter, and the only character in the whole commercial. ere was a lot to do, but you don't get these opportunities often where your effect is the only thing hap- pening in the spot." All the work Fusion CI did for this ap- plication paid off quickly. e day after the studio delivered the Fonterra simula- tions, it received a call for work on a music video wherein dancers turned into water. In less than two weeks, Fusion CI was able to adapt the tools from the earlier job and produce five shots for the video. Again, let- ting their creativity flow. n Karen Moltenbrey is the chief editor for Computer Graphics World. Mark Stasiuk from Fusion CI scripted the fluid-morphing technology used in the Whole water commercial through Python. Fluid Simulation n n n n

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