Feathers for Mystical Creatures: Creating Pegasus for Clash ......The Clash of the Titans feathers...
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Copyright is held by the author / owner(s). SIGGRAPH 2010, Los Angeles, California, July 25 – 29, 2010. ISBN 978-1-4503-0210-4/10/0007 Feathers for Mystical Creatures: Creating Pegasus for Clash of the Titans James Leaning * MPC Damien Fagnou † MPC Figure 1: Final rendered image c 2010 Warner Bros. Pictures Abstract One of the major challenges for Clash of the Titans was to develop a highly sophisticated feather system used on several flying char- acters in over a hundred shots. The system had to reliably provide photo-realistic results over a large range of detail levels from char- acters in the background to those passing just in front of the cam- era. The feather system was tightly integrated with MPC’s existing pipeline and allowed for a large amount of artistic freedom and con- trol efficiently, while requiring almost no technical background to use. 1 Feather Designing The foundation of the feather system’s high quality had to start with the initial design of individual feathers. It was essential that these feathers had to look realistic even very close up. To achieve this each feather barb was procedurally created as curves in full un- restricted three dimensions. This approach allowed these ’fluffy’ feathers to render with a full sense of volume. Fortunately there was already an advanced system for creating styled curves in the form of the ’Furtility’ fur/hair creation system. A feature was added to distribute fur on curves. This system al- lowed the groom artists to design feathers with the same powerful and flexible tools used for complex hair grooms. These feather templates could be used to create a infinite set of feather variations at render-time allowing every feather to be differ- ent. 2 Feather Distribution Additional targets were added to the the fur system that allowed the distribution of feather templates on polygon surfaces using ex- isting hair grooming tools. Feather distribution could use a variety of methods ranging from highly automated distribution to bespoke individual feather placement and sculpting. Tools were created to allow feathers to quickly align to surfaces, twist and stretch using control texture maps. These maps were created by the MPC 3D painting system. Weight painting was added to the painting system to allow additional flexibility in style selection. * e-mail: [email protected] † e-mail: [email protected] Figure 2: Final rendered image c 2010 Warner Bros. Pictures These feather distribution tools allowed the grooming artist to work with real-time visual feedback with a selection of visualization op- tions using actual feather designs. This previewing would actually match the final renders. 3 Animation and Dynamics The animators rig used a simple NURBS plane as a substitution for feather wings. This surface was then substituted with feathers at render-time, where additional procedural secondary animation could be applied for wind effects. For hero shots a technical Animation rig was used to allow a pass of dynamics, additional animation and tweaks which allowed the adjustment of proxies based on the actual feathers. 4 Rendering Due to the vast amounts of geometric data required to create such detailed effects, all feathers were created at render-time in a custom highly efficient multi-threaded PRMan DSO. In this process only blocks of feathers being rendered currently were generated and re- tained in memory at any one time, allowing each resulting final Pegasus render to contain tens of millions of curves. As only a compact set of parameters and maps were saved on disk, they could be reinterpreted at any LOD (level of detail) at render- time, tailored for each shots requirements using a simple slider. Ad- ditional automated LOD control would alter detail on a per feather basis based on the distance from camera and amount of motion blur. The feathers used a modified version of the existing advanced hair shader. While occlusion was traced against polygonal versions of the feathers generated automatically at render-time. 5 Summary The Clash of the Titans feathers presented many new and unique challenges that tested every part of our software to the limit. To achieve the high standard of work required in the short time-frame it was essential to build on existing tools and pipelines in ingenious ways, to guarantee the fast delivery of high quality work whilst still allowing the artist creative freedom and tool familiarity within the their shots.
Transcript of Feathers for Mystical Creatures: Creating Pegasus for Clash ......The Clash of the Titans feathers...
Copyright is held by the author / owner(s). SIGGRAPH 2010, Los Angeles, California, July 25 – 29, 2010. ISBN 978-1-4503-0210-4/10/0007
Feathers for Mystical Creatures: Creating Pegasus for Clash of the Titans
James Leaning∗
MPCDamien Fagnou†
MPC
Figure 1: Final rendered image c©2010 Warner Bros. Pictures
Abstract
One of the major challenges for Clash of the Titans was to developa highly sophisticated feather system used on several flying char-acters in over a hundred shots. The system had to reliably providephoto-realistic results over a large range of detail levels from char-acters in the background to those passing just in front of the cam-era. The feather system was tightly integrated with MPC’s existingpipeline and allowed for a large amount of artistic freedom and con-trol efficiently, while requiring almost no technical background touse.
1 Feather Designing
The foundation of the feather system’s high quality had to start withthe initial design of individual feathers. It was essential that thesefeathers had to look realistic even very close up. To achieve thiseach feather barb was procedurally created as curves in full un-restricted three dimensions. This approach allowed these ’fluffy’feathers to render with a full sense of volume.
Fortunately there was already an advanced system for creatingstyled curves in the form of the ’Furtility’ fur/hair creation system.A feature was added to distribute fur on curves. This system al-lowed the groom artists to design feathers with the same powerfuland flexible tools used for complex hair grooms.
These feather templates could be used to create a infinite set offeather variations at render-time allowing every feather to be differ-ent.
2 Feather Distribution
Additional targets were added to the the fur system that allowedthe distribution of feather templates on polygon surfaces using ex-isting hair grooming tools. Feather distribution could use a varietyof methods ranging from highly automated distribution to bespokeindividual feather placement and sculpting. Tools were created toallow feathers to quickly align to surfaces, twist and stretch usingcontrol texture maps. These maps were created by the MPC 3Dpainting system. Weight painting was added to the painting systemto allow additional flexibility in style selection.
∗e-mail: [email protected]†e-mail: [email protected]
Figure 2: Final rendered image c©2010 Warner Bros. Pictures
These feather distribution tools allowed the grooming artist to workwith real-time visual feedback with a selection of visualization op-tions using actual feather designs. This previewing would actuallymatch the final renders.
3 Animation and Dynamics
The animators rig used a simple NURBS plane as a substitutionfor feather wings. This surface was then substituted with feathersat render-time, where additional procedural secondary animationcould be applied for wind effects.
For hero shots a technical Animation rig was used to allow a passof dynamics, additional animation and tweaks which allowed theadjustment of proxies based on the actual feathers.
4 Rendering
Due to the vast amounts of geometric data required to create suchdetailed effects, all feathers were created at render-time in a customhighly efficient multi-threaded PRMan DSO. In this process onlyblocks of feathers being rendered currently were generated and re-tained in memory at any one time, allowing each resulting finalPegasus render to contain tens of millions of curves.
As only a compact set of parameters and maps were saved on disk,they could be reinterpreted at any LOD (level of detail) at render-time, tailored for each shots requirements using a simple slider. Ad-ditional automated LOD control would alter detail on a per featherbasis based on the distance from camera and amount of motion blur.
The feathers used a modified version of the existing advanced hairshader. While occlusion was traced against polygonal versions ofthe feathers generated automatically at render-time.
5 Summary
The Clash of the Titans feathers presented many new and uniquechallenges that tested every part of our software to the limit. Toachieve the high standard of work required in the short time-frameit was essential to build on existing tools and pipelines in ingeniousways, to guarantee the fast delivery of high quality work whilst stillallowing the artist creative freedom and tool familiarity within thetheir shots.
