Painterly Rendering for Animation – Barbara Meier Presented by - Kash

Outline Art based Comparison to Other work How it works Results

Art based Don’t show everything Leave a level of abstraction No Plastic Look

Art Details abstracted by short hand brush strokes, larger brush strokes for background Roundness of forms should be defined by brush stroke directions Color should break boundaries of surfaces to create rhythm in the composition Brush stroke size and texture should be varied according to the kind of surface Effects of Light should be exagerated

Example

Comparison to Other Work No “Shower Door” effect No Random Noisiness Maintain Coherence (3d particle, 2d brush strokes) Stick brush strokes on the model and not the screen. Randomize it. Better than texture mapped approaches (silhouettes)

Example

Example (w Brush Strokes)

How it Works Surface Particles placed in world space Reference images rendered Each particle becomes a screen space stroke

Algorithm create particles to represent geometry for each frame of animation create reference pictures using geometry, surface attributes, and lighting transform particles based on animation parameters sort particles by distance from viewpoint for each particle, starting with furthest from viewpoint transform particle to screen space determine brush stroke attributes from reference pictures or particles and randomly perturb them based on user-selected parameters composite brush stroke into paint buffer end (for each particle) end (for each frame)

Pipeline

Particle Generation Compute Area of surface triangles Randomly place particles on traingles - Number of particles placed per triangle are proportional to the surface area

Reference Images Brush Strokes defined by Image Color Orientation Size Position

Stroke Rendering Particle transformed to screen space Stroke parameters from reference images Changed according to any user specification Brush image rendered according to stroke parameters Grayscale brushes may be used Grayscale textures may be used

Example

Layered Rendering Similar objects rendered together Different objects rendered differently and in specific order Strokes do not intrude other objects

Example

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Questions