RealTime Dynamic Wrinkles Caroline Larboulette MariePaule Cani GRAVIR
Real-Time Dynamic Wrinkles Caroline Larboulette Marie-Paule Cani GRAVIR Lab, Grenoble, France
Motivations Animated wrinkles • Important for realism Static wrinkle – Cloth – Skin • Currently painful under MAYA – Key shapes – Deformers Aims Dynamic wrinkles • Real-time for computer games • Applicable to a coarse animated mesh • Easy to set up
Previous Work • Bump mapping [Blinn 78, Boissieux 00, Pasquariello 01] – Efficient but undeformed silhouette • Physically-based approaches [Wu 94 -99, Boissieux 00] – Very realistic but slow • Predefined Wrinkles [Viaud 92] – Specific mesh incorporating wrinkles • Displacement mapping [Volino 99, Hadap 99, Bando 02] – The user designs the wrinkle pattern
Our Wrinkling Tool Basic Idea skin/cloth wrinkle because they tend to maintain area – Physically-based simulation, geometric constraints [sauvage 04] ? Aims – Fast approximation of constant surface – No manual design of the wrinkles shapes – Provide control of location and main direction of wrinkles Our solution – A constant length wrinkling curve – Controls the mesh deformation in a region of influence
Wrinkling Curve • 2 D discrete curve of constant length • Different propagation schemes • Control of frequency, width of the bumps
Set up of the Wrinkling Tool 1. Draw a line segment • 2. Specify a region of influence • 3. End points are anchored to the mesh Points under the green rectangle Choose an attenuation profile
Mesh Deformation • • Mesh animated by standard skinning Wrinkles updated just before rendering Algorithm 1. 2. 3. Update 2 D curve due to length changes Refine mesh if needed Compute mesh vertices displacements • • Height given by the coordinate along the curve Weighted according to the attenuation profile
Levels of Details • Combination of bumps at different scales • Absorbs compression at different resolutions
Multi-Wrinkles • Combination of several wrinkles
Results: forehead wrinkles
Results: joint wrinkles Without our tool With our tool
Results: wrinkles on clothes Back Front
Video and demo
Conclusion • Procedural technique – Mesh refined on the fly – Could depend on other parameters (camera) • Easy-to-use for animators – Use of any existing skinning animation – Intuitive parameters and visual feedback • Geometric constraints (length preservation) – Increases realism • Real-Time
Future Work • Curved Wrinkles • Collision detection • Combination with a dynamic flesh model
Thanks. . . Questions ?
- Slides: 16