Real-Time Dynamic Wrinkles Caroline Larboulette Marie-Paule Cani GRAVIR Lab, Grenoble, France.
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Transcript of Real-Time Dynamic Wrinkles Caroline Larboulette Marie-Paule Cani GRAVIR Lab, Grenoble, France.
Motivations
Animated wrinkles • Important for realism
– Cloth– Skin
• Currently painful under MAYA– Key shapes– Deformers
Aims• Real-time for computer games• Applicable to a coarse animated mesh• Easy to set up
Static wrinkle
Dynamicwrinkles
Previous Work
• Bump mapping [Blinn78, Boissieux00, Pasquariello01]
– Efficient but undeformed silhouette
• Physically-based approaches [Wu94-99, Boissieux00]
– Very realistic but slow
• Predefined Wrinkles [Viaud92]
– Specific mesh incorporating wrinkles• Displacement mapping [Volino99, Hadap99, Bando02]
– The user designs the wrinkle pattern
Our Wrinkling Tool
Basic Ideaskin/cloth wrinkle because they tend to maintain area
– Physically-based simulation, geometric constraints [sauvage04] ?
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
• 2D 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• End points are anchored to the mesh
2. Specify a region of influence• Points under the green rectangle
3. Choose an attenuation profile
Mesh Deformation
• Mesh animated by standard skinning• Wrinkles updated just before rendering
Algorithm1. Update 2D curve due to length changes2. Refine mesh if needed3. 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
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