3. Stylization of 3D Animations 3D scene 2D appearance Stylized color regions 2D medium: a pattern Temporal coherence 3 Paint strokes Pencil strokes Paper Watercolor pigments
6. Temporal Coherence Problem Extreme cases Requirements 6 Flatness Shower-door Popping Coherent motion Temporal continuity Traditional mapping Contradictory requirements: solution find a compromise
7. 3 goals to ensure at best Additional challenges Flexibility variety of styles Interactivity artistic control Evaluation quality of the trade-off Flatness Coherent motion Temporal continuity 7
19. Gabor Noise [LLDD09] Offers significant spectral control Support anisotropy Is fast to evaluate 17 See “State of the Art in Procedural Noise Functions”, EG 2010 for comparisons with previous work
20. Gabor Noise [LLDD09] Definition Sum of randomly positioned and weighted kernels 18 Gabor kernel noise random positionsand weights
31. Style Design Standard techniques from procedural texturing and modeling [EMPPW02] Threshold Smooth step function X-toon textures [BTM06] Compositing (alpha-blending, overlay) Local control Curvature noise orientation Shading noise frequency Interactivefeedback Threshold texture 27
37. User Study: Motivation Evaluate success of various solutions according to Relative importance of these criteria 33 Flatness Coherent motion Temporal continuity
38. User Study: Setup Methodology 15 naïve subjects, ~ 20-30 minutes Ranking tasks “Rank the images/videos according to … ” 34
39. User Study: Compared methods 35 Local screen-space Global screen-space Object-space Adv D2D DST ours SD TM Extreme cases
66. User Study: Flatness “Rank the images according to how flat they appear.” Simple stimuli Complex stimuli less flat more flat less flat more flat 50 50
67. User Study: Coherent motion “Rank the videos according to how coherently the pattern moves with the object.” Simple stimuli Complex stimuli Object-space translate: rotate: zoom: more coherent less coherent less coherent more coherent 51
68. “Rank the videos according to how much the pattern changes over time.” Simple stimuli Complex stimuli User Study: Temporal continuity translate: rotate: zoom: more change less change more change less change 52 52
69. User Study: Pleasantness “Rank the videos according to how pleasant you find them in the context of cartoon animation.” Complex stimuli Object-space less pleasant more pleasant 80 53
Editor's Notes
In complement to our analysis of previous work on the triangle of requirements, we would like to evaluate how final viewers actually perceive these tradeoffs. We believe that such study can provide significant insight into how well previous solutions, including ours, perform for each goal: flatness: how much is the pattern perceived as produced in 2D coherent motion: how closely is the pattern following the 3D motion of the scene and temporal continuity: how much does the pattern change over timeBesides, this study may give an indication of the relative importance of these criteria. That is if the choice of an equilateral triangle is meaningful.
The results for motion coherence and pleasantness exhibits least variance and are strongly correlated.This indicates that motion coherence is probably the most important quality to preserve in the overall temporal coherence compromise.Both Dynamic Solid Textures and our method perform well on the motion coherence scale: the first one trades off better temporal continuity, whereas ours trades off better flatness.