Game Development Reference
In-Depth Information
Chapter 5
A Uniform Geometry Workflow
for Cutscenes and Animated
Feature Films
Adrien Herubel, Venceslas Biri, Stepane Deverly, Antoine Galbrun
At DuranDuboi, as we started the preproduction of our first animated feature film in 2009 it became clear that our
VFX production pipeline was no longer adequate. Instead of small, manageable projects involving a few generalists,
we were now dealing with massive amounts of data requiring intense, short-term efforts from multiple teams of
specialists. So with a relatively low budget, we focused on developing from scratch an efficient workflow for handling
the massive amount of geometry produced by the different production departments.
But manipulating dynamic geometry is costly both in terms of computing power and storage. For example, the
complex Autodesk Maya rigs on the main characters take nearly 60ms per frame to evaluate. In a typical shot, two
or three of these characters will be present, making the sequence impossible to animate in real-time. Even worse,
dynamic cloth and hair simulations can take up to a minute per frame to compute. Therefore, we decided that
geometry should be precomputed or baked whenever possible.
Our key idea was to rely on a single geometry cache format tailored for efficient read, plugged into every software
package we used, from modeling to compositing and rendering. Our ubiquitous cache system allowed us to design
a set of tools for modification and visualization of the files. Those tools were used uniformly across the production
pipeline and allowed us to reduce the usage of Maya, especially for automated geometry processing and quality
control.
Moreover, this uniform geometry pipeline improved our workflow by allowing multiple departments to work
simultaneously and reduced the overall computational and storage costs. As it turned out, we weren't the only ones
thinking along these lines. Sony Pictures Imageworks simultaneously developed the basis of a similar solution,
Alembic, which is an open interchange format focused on efficiently storing baked geometry (
www.alembic.io
).
Alembic has now grown into a production-proven solution; it is stable and efficient enough to serve as the exchange
format and API to implement the same pipeline as presented here. In this chapter, I will describe the four parts of our
cache and show how it is integrated into our workflow.
Technology
Our cache system can roughly be divided into four parts: a low-level binary cache format, an I/O framework,
commercial software plug-ins, and tools (see Figure
5-1
).
