Manuel Mesters - Subdivision Surfaces computer graphics & visualization Seminar Computer Graphics Geometric representation and processing: Subdivision Surfaces
computer graphics & visualization Manuel Mesters - Subdivision Surfaces At a glance Refinement 1Refinement 2 Refinement ∞
computer graphics & visualization Manuel Mesters - Subdivision Surfaces At a glance
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Outline - Motivation: Geri’s Game - Introduction: Subdivision Basics - Loop Subdivision Surfaces - Catmull-Clark Subdivision Surfaces - Summary
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Outline - Motivation: Geri’s Game - Introduction: Subdivision Basics - Loop Subdivision Surfaces - Catmull-Clark Subdivision Surfaces - Summary
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Making of Geri‘s Game
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Geri’s Game - 1st animation using Subdivision Surfaces - Playground for new technologies - Best Animated Short (1997)
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Draft s of drawings
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Clay Models - Double Life Size Model: - Head - Hands
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Digitizing - Laserscanner -> Point Cloud
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Mesh - Point Cloud -> Mesh - Controls for facial movements (manual insertion)
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Animation Process - Using Pixar’s RenderMan: - Animate Mesh - Call Controls / Subdivide
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Cloth Dynamics - Dynamic flexible mesh - Energy functions - Many equations...
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Watch Geri’s Game
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Outline - Motivation: Geri’s Game - Introduction: Subdivision Basics - Loop Subdivision Surfaces - Catmull-Clark Subdivision Surfaces - Summary
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Subdivision - Definition Subdivision defines a smooth curve or surface as the limit of a sequence of successive refinements
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Subdivision - Definition Subdivision defines a smooth curve or surface as the limit of a sequence of successive refinements - Start: Control Mesh - Process: Apply refinement rules (many times) - Result: Smooth curve/surface
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Subdivision Curve Start: Polygon Apply refinement rule Result: Smooth curve
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Subdivision Curve - Rules
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Subdivision Curve
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Different Algorithms - Different Results Loop Catmull-Clark Butterfly Doo-Sabin
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Different Algorithms - Different Results Loop Catmull-Clark Butterfly Doo-Sabin
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Outline - Motivation: Geri’s Game - Introduction: Subdivision Basics - Loop Subdivision Surfaces - Catmull-Clark Subdivision Surfaces - Summary
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Loop Subdivision
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Loop Subdivision original vertex v3 v1v2 v4
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Loop Subdivision edge point (ep): constructed on each edge original vertex v3 v1v2 v4 ep
computer graphics & visualization Manuel Mesters - Subdivision Surfaces vertex point constructed for each old (original) vertex Loop Subdivision edge point original vertex
computer graphics & visualization Manuel Mesters - Subdivision Surfaces vertex point: constructed for each old (original) vertex Loop Subdivision A given vertex has n neighbor vertices. The new vertex point: For n = 3 For n > 3 v v
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Loop - Local Subdivision - Exclude some edges from Subdivision - More details later...
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Outline - Motivation: Geri’s Game - Introduction: Subdivision Basics - Loop Subdivision Surfaces - Catmull-Clark Subdivision Surfaces - Summary
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Catmull-Clark Subdivision
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Catmull-Clark Subdivision FACE EDGE
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Catmull-Clark Subdivision FACE EDGE
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Catmull-Clark Subdivision FACE EDGE VERTEX
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Sharp creases - Subdivision produces smooth surfaces 1.Tag Edges as “sharp” or “not-sharp” During Subdivision, 2.if an edge is “sharp”, use sharp subdivision rules. 3.If an edge is “not-sharp”, use normal smooth subdivision rules.
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Infinitely Sharp Creases - Tag Control vertices and edges as sharp - Face points: same as smooth rule - Edge points: place at midpoint of edge - Vertex points - One sharp incident edge (dart): same as smooth rule - Two sharp edges (crease): (e 1 + 6v i + e 2 ) / 8 - Three or more sharp edges (corner): do not modify point
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Sharp rules FACE (unchanged) EDGE VERTEX crease dart corner >2 2 0,1 # adj. Sharp edges
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Semi-sharp creases 1.Tag Edges as “sharp” or “not-sharp” n = 0 : “not sharp” n > 0 : sharp During Subdivision, 2.if an edge is “sharp”, use sharp subdivision rules. Newly created edges, are assigned a sharpness of n-1. 3.If an edge is “not-sharp”, use normal smooth subdivision rules.
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Subdivision - Sharpness!
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Outline - Motivation: Geri’s Game - Introduction: Subdivision Basics - Loop Subdivision Surfaces - Catmull-Clark Subdivision Surfaces - Summary
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Summary Take home message
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Summary Subdivision defines a smooth curve or surface as the limit of a sequence of successive refinements
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Summary
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Summary - There are different Algorithms - Mesh Type - Rules
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Summary - Loop - Catmull-Clark
computer graphics & visualization Manuel Mesters - Subdivision Surfaces Summary - Subdivision - Standard rules -> smoothness - Additional rules -> sharpness - Sharpness parameter -> flexibility
computer graphics & visualization Manuel Mesters - Subdivision Surfaces The End Thank you for your attention