Carbon 3D : A RealFlow Case Study

Carbon 3D : A RealFlow Case Study from Fusion CI Studios

Fusion CI Studios is committed to excelling at complex dynamic fx challenges. Realistic physical simulation is the core of their work – complex fluid and particle fx like smoke, fire, explosions and rigid/soft body dynamics at uncompromising, photo-real, feature-film quality.

…When Carbon 3D announced its groundbreaking 3D printing process, CLIP, at a Vancouver TED talk, Fusion CIS partnered with Cinco Design to create an artistic depiction of how the printer works using RealFlow and other software.

The Challenge

Fusion’s fluid & particle effects had to artfully represent the 3D printer’s unique chemical reaction of laser-lights and liquid resin that, as if by magic, creates a 3D object. With only three weeks to sim & render 1) a complex, original particle fx “nebula”, 2) a photo-real droplet traveling through space and 3) a viscous fluid elegantly interacting with intricately detailed ‘buckyball’ geometry, the challenge was intense.

The Process

Cinco created previz maya scenes containing a rising, intricate “buckyball” + cameras for all shots above the surface of the resin bath. Fusion devised a nebula particle system of 12 elements and more than 300 million particles, using RealFlow, Fume FX and Krakatoa. From each RealFlow particle set, different characters of swirly Fumefx sims were generated, some rapidly moving and dispersing, others slower and more concentrated on their sources. Fusion then varied the density slicing settings when generating Krakatoa particles, In the render, different elements were assigned different color variations with age, based on the approved color palette.

The photo real droplet was simmed at a high fps, rendered with shallow depth of field and some simulens lens flaring. Key to rendering transparent liquids is reflecting and refracting the environment. With this droplet coalescing at the center of a swirling nebula, that’s the environment Fusion used.

Several shots followed where the 3D printed buckyball ascends from its resin pool. The challenge was to make it feel like the buckyball was actually forming from an illuminated zone just below the fluid surface. Given the timeframe, this was best achieved not by morphing, but through lighting, shading and compositing. Despite complex geometry naturally capturing & containing liquid as the buckyball rose, the creative required any excess fluid to slip off the object just a little above the surface.

So Fusion created a scripted forcefield, “the cleaner”, affecting only particles touching the geo above the liquid surface. The cleaner pushed particles parallel to their colliding face, in a direction as parallel to vertically downward as possible. This gave the fluid a slightly lively movement, quite similar to the unique motion of excess resin in the actual printing process.

The Result

Maxwell renders beautiful, realistic depth of field blur, but to make it look smooth you have to go to quite high SL (sampling level). That, combined with internal illumination of the liquid, meant render times of 8 to 10 hours per frame, in a piece with more than 1440 frames and a tight turnaround. Fusion focused on the creative directive of internal illumination rather than achieving accurate depth of field blur, then rendered to the highest SL in the time available. Cinco composited and finished, adding lens flares, atmospheric fogs, and depth of field blur. The result? Mesmerizingly beautiful fx. In fact, Fusion was so inspired they created a side-story starring the Carbon 3D RealFlow bubble, Genesis.

Genesis

Carbon 3D : A RealFlow Case Study