Feature-Based Mesh Editing Qingnan Zhou 1 Tino Weinkauf 1,2 Olga Sorkine 1,3 1 NYU 2 MPII Saarbrücken 3 ETH Zürich

Deformation

Detail Preserving [Sorkine et al. ARAP Surface Modeling, SGP 07]

Detail Preserving Deformation Structure Preserving [Gal et al., iWires, SIGGRAPH 2009]

Deformation Detail Preserving Structure Preserving Feature Preserving Original [Sorkine et al. ARAP Surface Modeling, SGP 07] Our result

Feature-Based Mesh Editing InputFeature ExtractionResult of feature editing

Features What are features? – In words, features are where surface normal changes abruptly. – In pictures:

Features What are features? [Hildebrandt et al., Smooth Feature Lines, SGP05] – In math: local minimum and maximum of principle curvatures in their corresponding directions. Local maximum Cross Section

Features What are features? [Hildebrandt et al., Smooth Feature Lines, SGP05] – In math: local minimum and maximum of principle curvatures in their corresponding directions. – Zeros of e max that satisfy the following (similar constraints apply to e min ) Extremality: Salient constraints:

Features What are features? – In practice: InputValley lines (blue) Zeros of e min Ridge lines (yellow) Zeros of e max

Feature-Preserving Optimization Idea: if curvature values are preserved, so are their local minima and maxima, and so are the features, right?

Feature-Preserving Optimization Idea: if curvature values are preserved, so are their local minima and maxima, and so are the features, right? – Answer: possibly. – Concern 1: what about principle curvature directions? – Concern 2: non-convex energy?

Feature-Preserving Optimization Energy Formulation:

Feature-Preserving Optimization Energy Formulation: Curvature Preservation:

Feature-Preserving Optimization Energy Formulation: Conformality:

Feature-Preserving Optimization Energy Formulation: Positional constraint:

Feature Manipulation Feature-preserving deformation: [Sorkine et al. ARAP Surface Modeling, SGP 07] Our result: original curvature preserved Original

Feature Manipulation Feature-preserving deformation: [Sorkine et al. ARAP Surface Modeling, SGP 07] Our result: original curvature preserved Original

Feature Manipulation Feature smoothing and sharpening: Original FeaturesOur result

Feature Manipulation Feature smoothing and sharpening: OriginalFeatures smoothed Original Features sharpened

Feature Manipulation Feature creation: OriginalOur result

Feature Manipulation Feature creation: OriginalUser drawn features Red: ridge Blue: valley Our result

Summary We have presented a feature-based deformation system. Our experiments give optimistic results. Future work: – Check for conflicting constraints. – Theoretic support of the idea. – Try meshes with less pronounced features.