Introduction Background Design Implementation Results 2 - - PowerPoint PPT Presentation

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Introduction Background Design Implementation Results

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Introduction

• Use dynamics to interpret motion data in an artistically-inspired way
• Motion sculptures that represent moments in time, yet escape the constraints
• f the human range of motion
• Museum walkthrough to showcase the sculptures

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Capturing Motion

Hea ead-spr pring by Eadward Muybridge, 1887 Bullet et Time e by Manex VFX, 1 1999

• Playback sequence of still images to produce an animation
• Muybridge’s camera array

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Motion and Art

• Marey’s Chronophotography
• Inspired French Cubism & Italian Futurism
• Moved away from analytical portrayals of movement

So Somersault over a an o

• bstacle by Etienne-Jul

ules s Marey ey, 1 1884

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French Cubism

• Inspired by the idea of motion as the subject matter
• Reconstruction of time and space
• Multiple viewpoints together
• Geometric shapes and repetition

Nude Descend nding ng a a Staircase se, N

• No. 2

2 by Marcel D Duchamp, 1912

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Italian Futurism

• Inspired by the innovations in photography
• Photodynamism, dynamic photography
• Focused on overall motion
• Time is the brush on a spatial canvas
• Aimed to provoke a sensation

The Cellist by Anton Braga gagl glia, 1 1913

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Performance Capture

Nike S Sports s Rese search L h Lab Dawn o

• f t

the e Planet et o

• f the A

e Apes es, 2014 014 Hea ead-spr pring by Eadward Muybridge, 1887

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Using Technology to Create Art

Line Drawing as a Dynamic Process

Donald House and Mayank Singh, Texas A&M University, 2007

Simulates gestural, free-flowing drawing techniques and incorporates momentum and pen pressure

• Inspired by dance and stage
• Theatrical lighting
• Accentuates form and contour
• Guides narrative and focus
• Shapes and shadows

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Designing the Environment

• Based on modern art museums

Caught ht by David P Parsons

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Designing the Sculptures

• Basis in reality, yet impossible
• Recreate the sensation of motion
• Inspired by Cubism, Futurism,

Light-painting photography

Breakdance Light Painting by J Joanna Jask skolsk ska

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Working with Motion Capture Data

• Reflective Markers and Infrared Cameras
• Spatial location of markers used to rebuild joint rotations
• Several ways of translating the data

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Applying Dynamics

• Motion capture animation is transferred to a set of control points
• Corresponding set of pen points
• Spring connection between each pair
• Preserves momentum and extends reach
• Creates smooth trajectory of motion

Source: Line Drawing as a a Dynamic Process ss by D Donald House a and May ayan ank Singh, 2007 007

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Springs, Proportional-Integral-Derivative Controller

t current time 𝑛 mass of pen 𝑞 position of pen 𝜐 position of control 𝑓 error 𝑙, 𝑒, 𝑑 corrective gains 𝜕 natural frequency 𝜂 damping constant 𝑒2𝑞 𝑒𝑒2 = −𝜕2𝑓 − 2𝜂𝜕𝑒𝑒

𝑒𝑒

𝑒2𝑞 𝑒𝑒2 = − 1

𝑛

𝑙𝑓 + 𝑒𝑒𝑒

𝑒𝑒 + 𝑑 𝑓𝑒𝑒



Source: Line Drawing as a a Dynamic Process ss by D Donald House a and May ayan ank Singh, 2007 007

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Applying the Forces

• Control points from motion capture data
• Pen points created as particle system
• Spring forces implemented in Python/VEX code

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Point Attributes

• Varying spring constants
• Velocity-based scaling
• Color variation

Motion C Capture Data Spring Forces, V Variation 1 1 Spring Forces, V Variation 2 2 Spring Forces, V Variation 3 3

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Building the Sculptures

• 5 small animated sculptures
• Pen points create trail
• Simple extrusions along curves
• Animation controls
• Time offsets within sculpture
• Direction variation
• Dissolve Effect
• Noise Effect

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Building the Sculptures

• 5 large stationary sculptures
• More complexity
• Not restricted to simple extrusions
• Layers of motion
• Noise patterns
• Refinement of “unnatural”

imperfections

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Building the Sculptures

Using OpenVDB to fix non-manifold geometry

Mesh w with i intersections Converted to OpenVD VDB Level elset et

1. 2.

Smooth m mesh without i inner p penetrations Convert Level elset et back t to mesh sh

3.

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Attribute-based Shading

Create a “hand-made” feel by adding specular and diffuse noise, grunge, and bump

Unalter ered ed shader Attribute v visualization Attribute-based s shading

• Edge detection by measuring curvature of surface
• Mixed with noise pattern
• Artist can paint on attributes

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Results

• Workflow can be applied to any animated point data
• Motion Capture
• Keyframe Animation
• Particle Systems
• Custom VEX spring solver

in Houdini DOPs

• Point manipulation tools
• Procedural modeling tools

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Sculpture from a animated s sphere: with ( (left) a and without (right) spring dynamics Sculpture from p particle s system w with s spring dynamics

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Thank you

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Questions