This is a continuation of the series of posts started here.

Character Rigging, Deformations, and Simulations in Film and Game Production

Character animation is one of those areas where film and game production have intriguing similarities as well as differences; especially in the ways that the character meshes deform in response to animation and simulation. This course includes three talks, each covering a different application domain: games, visual effects, and feature animation. These talks will be presented by:

• David Coleman (Senior CG Supervisor, Electronic Arts Canada). David (who has worked at Electronic Arts for 15 years and is currently responsible for the central team that provides rigging for many of EA’s sports titles) will present the games portion of the course. He will discuss character rigging, deformations and simulations in game production, emphasizing the technical restrictions imposed due to the real-time and interactive nature of games. This talk will also cover some strategies for setting up procedural secondary rigging systems in Maya, MotionBuilder and at run-time in games.
• Tim McLaughlin (Department Head and Associate Professor, Department of Visualization at Texas A&M University). Tim (who had 13 years of experience at ILM – most of it on digital creatures – before heading the Texas A&M Department of Visualization) will discuss rigging for visual effects. He will cover the unique requirements brought on by integration with live action but also the affordances offered by the limited range of scope of performance requirements relative to feature animation and games. Tim will discuss rigging modularity, provisions for animator control, non-linear deformations, areas of highest importance for deformations, and the efficient use of muscle systems.
• Larry Cutler (Supervising Character TD, DreamWorks Animation). Larry (who worked at Dreamworks Animation for 10 years, and at Pixar for four years previously) will be discussing rigging issues for feature animation. Larry’s talk will deal with the impact of character design, modeling, and scalability for thousands of shots on rigging, deformation, and simulation. He will discuss the issues arising from the unique needs of feature animation: accommodating for extreme range of motion, and increased emphasis on art directability and animator control. Larry will also cover hair, cloth, and facial animation systems.

Destruction and Dynamics for Film and Game Production

Another “X for film and games” course, this time focusing on rigid body dynamics and destruction / fracturing methods. The course will cover production aspects such as authoring tools and game engine integration, in addition to the computational and algorithmic aspects. Like the last course, this one will highlight interesting commonalities and differences between film and game practice. There are areas where each can learn from the other: the film techniques can point the way to future methods for games running on more powerful platforms; and the efficient game methods are useful for fast prototyping, previsualization and even speeding up final shots in film.

The course will start with a 30-minute presentation by the course organizer, Erwin Coumans (Principal Physics Engineer, AMD). Erwin has worked on physics in games for over a decade, and is also the main author of the open-source Bullet Physics Library. Although Bullet was originally designed for game use, it has been used on many films as well, including big-budget Hollywood blockbusters such as How to Train Your Dragon, Sherlock Holmes and 2012. Erwin will give an overview of the course, as well as a brief introduction to the basic theory of rigid body dynamics and destruction/fracturing methods. He will also cover collision detection and handling contacts, approximate methods for the modeling of stress and strain, and how to decide when and where to break rigid bodies into several parts. The course will continue with the following talks:

• Authoring Destruction With the Dynamica Bullet Maya Plugin (15 minutes), by Michael Baker (Faculty, Art Institute of Las Vegas): Michael has worked on Las Vegas casino games, visual effects for various short films and games, and the Bullet Physics Library (in particular the Dynamica Maya plugin which is the primary topic of his talk). Michael will discuss the development and use of Dynamica to support choreographed rigid body behavior such as progressive crumbling of pre-shattered objects, sequential structural failure and timed directional explosions.
• Destruction and Dynamics Artist Tools for Film (45 minutes), by Nafees Bin Zafar (Senior Production Engineer, Dreamworks Animation) and Mark T. Carlson (Lead Engineer, Dreamworks Animation): Nafees has worked on simulation and volumetrics tools (both at Dreamworks and in his previous job at Digital Domain) for over ten years, winning a Scientific and Engineering Academy Award in 2007. Mark has worked on cloth, fluid and crowd simulation for six years at DNA Productions, Walt Disney Animation and Dreamworks Animation. This talk will cover 3rd party software integration in the movie pipeline, building artist tools with Bullet, and authoring of destruction using Maya and Houdini. Examples from recent Dreamworks Animation movies will showcase the techniques described.
• Deformable Rigid Bodies and Fragment Clustering for Film (45 minutes), by Brice Criswell (Senior Software Engineer, Industrial Light & Magic): Brice has been developing production related software for 12 years with ILM, and specializes in rigid body and crowd dynamics. Brice’s talk is divided into three presentations. The first discusses a deformable rigid system which efficiently simulates on-impact bending and denting of normally rigid bodies. The second covers a fragment clustering system which allows artists to initialize sets of geometry as a single rigid body, then dynamically break the objects during the progression of the simulation. The third presentation covers the challenges involved in animating, simulating, and deforming the tentacle beard of the Davy Jones character in the Pirates of the Caribbean movies. Each of the talks will detail algorithms as well as production issues, and will include VFX production examples from prominent feature films.
• Procedurally Generating Fragmented Meshes for Games (15 minutes), by Phil Knight (Lead Programmer, Avalanche Software – a division of Disney Interactive Studios): Phil has 13 years of game development experience, working most recently on Cars 2, Toy Story 3, and Bolt, and previously on the Links and Amped series. His talk will cover a procedural technique for automatically generating fragmented meshes, especially useful for modeling large explosions with lots of fragmentation and debris. Besides detailing the technique itself, Phil will also describe the fragmentation tool (‘Frag’) which implements it, and its use in game production at Disney Interactive Studios.
• Accelerating Rigid Body Simulation and Fracture Using the GPU (30 minutes), by Takahiro Harada (Researcher, AMD): Takahiro Harada has performed research and development into physics simulation at The University of Tokyo and Havok as well as his current position at AMD (where he focuses on the use of GPU computing for physics simulation). He will present a GPU-based rigid body simulation which can be used to quickly simulate the large numbers of rigid bodies typically created by object destruction. The talk starts with an overview of the simulation and proceeds to the detailed GPU implementation of each stage of the simulation.

PhysBAM: Physically Based Simulation

Similarly to the previous course, this is targeted at physics simulation and has strong ties to film production. However, its structure is very different; instead of covering a variety of production examples, it focuses on one code library – PhysBAM, initially developed by Ronald Fedkiw and continued by him and many others at Stanford. PhysBAM is used by many VFX and feature animation houses including ILM, Disney Animation, and Pixar; large portions were recently released under an open-source license. This course is presented by Craig Schroeder (PhD Student, Stanford Computer Science Department); it will cover information on the PhysBAM library release: how to obtain the source code, set up the library, and use it to run example smoke and water simulations, as well as descriptions of visualization and rendering tools included in the release. In addition to the PhysBAM library, the course will explain the underlying techniques that make these simulations possible, in particular level set methods such as fast marching, fast sweeping, and the particle level set method. It will also address the important aspects of a fluid simulation, including advection, viscosity, and projection.

There are 12 courses left to cover; I’ll do so over my next few blog posts.