A New Interface Paradigm for Motion Capture Based - Visgraf

A New Interface Paradigm for Motion Capture Based - Visgraf
A New Interface Paradigm for
Motion Capture Based
Animation Systems
Fernando Wagner da Silva
Luiz Velho
Jonas Gomes
Paulo Roma Cavalcanti
IMPA - Instituto de Matemática Pura e Aplicada
LCG - COPPE/SISTEMAS - UFRJ
Rio de Janeiro - Brazil
General Outline
● Computer
Animation
● Motion
Capture (MoCap)
● MoCap
Animation System
●A
Graphic Interface for MoCap
● Conclusions
● Future
work / Work in progress
Computer Animation
● Keyframing
– interpolation between key poses.
● Procedural
– procedure parameters over time.
● Simulation
– physical constraints and rules.
● Motion
Capture
– sampling at points of a real subject.
Motion Capture
● Advantages
– natural looking motion.
– speed of production.
● Drawback
– data complexity and size.
Motion Capture
● MoCap
is different from traditional
animation data
● Existing
systems are not suitable for
MoCap processing
Our Motivation
● To
build an animation system focused
on MoCap
● To
represent well MoCap abstractions
● To
implement a set of motion
operations with associated interface
tools
● The
system will serve as a “testbed”
for new operations and techniques
Characteristics of Our Animation
System
● MoCap
as main animation tool
● Modular
architecture
(Input, Processing, Output and Interface)
● Specialized
GUI objects sharing a
dynamic state structure
System’s Basic Entities
● Virtual
Actor (skeleton)
– topology: graph (joints+links).
– geometry: connected limbs.
Reflects the structure of an articulated figure
System’s Basic Entities
● Motions
– sampled parameters over time.
System’s Architecture
Interface
Input
Processing
Data
Structures
Output
System’s Architecture
Input
Processing
Output
• Motion operations
• Interpretation
• Pre-processing
• Relative angle extraction
• Reusable motion
libraries
• MoCap format
converter
System’s Architecture
Interface
Data
Structures
• Entities
• Operations
• Control
• Actor
• Motions
A Graphic Interface for Motion
Capture
● Focus
of this presentation
● Objectives
– represent the abstractions used in MoCap.
– provide a correct control of the operations.
– extensible: new operations and techniques.
●
Starting point Paradigm :
post-production video workstations
Basic GUI Elements
● Actor
● Motions
● Motion
● Other
Operations
Objects (control)
Actor
● Skeleton
topology + geometry
• Visual information
about the hierarchy
• Different styles of
representation
Motions GUI Elements
● Motion
Bar
● Motion
/ Joint
● ScratchPad
● Motion
● Joint
Curves
Window
Motion Bar
● Each
motion is a potentially ready
animation
● We
treat each motion as a horizontal bar
Motion length
Placement
Frame
Resize
Motion / Joint
• Connects actor and motion descriptions
• Acts as a zoom into the motion bar
• Useful to select a set of joints
ScratchPad
● Motion
organizer & container
Motion rails
Motion time
Additional info
Gateway between
Input and Processing
Modules
Motion Curves
● Associated
with actor’s joints
Graphical
representation
Additional numeric information
GUI object allows curve editing
Joint Curves
Different data channels
Motion Operations
● Filtering
(unary)
● Concatenation
(n-ary)
● Blending
(usually binary)
● Warping
(unary)
Motion Filtering
Filter
parameters
Selected region
• Allows region selection
• Operation to a specific set of joints
(using Motion/Joint GUI object)
Motion Concatenation
Blending intervals
• Interactive motion positioning / resize
• Interactive definition of blending interval
Motion Blending
Time-markers
• Interactive motion positioning / resize
• Sequence of time-markers match events in time
Motion Warping
Keyframes & region for Warping
Warp
parameters
• Interactive modification of warp frame using
forward kinematics
• Interactive positioning of keyframe constraints
Other Objects - Camera
Zoom in
Zoom out
Follow mode
Lock joint mode
Circle camera
• Interactive control of camera settings
• Controls adapted for MoCap
Other Objects - Playback
Frame slider
Controls &
additional info
• Control panel similar to VCR
• Precise frame control
• Real-time preview using OpenGL
Other Objects - Additional Features
● Interactive
forward kinematics joint
control
● Keyframing
Implementation Issues
●C
Language + UNIX
● Rendering:
● Standard
GUI facilities: XForms
● Real-time
● Tested
OpenGL
frame rates
on SGI, RS6000 and Linux
Conclusions
● MoCap
based systems
– correct representation of MoCap abstractions.
– integration with capturing systems.
– what is the minimum set of operations?
● Proposed
GUI paradigm
– correct representation of the problem.
– intuitive.
– easy integration of new techniques.
Future Work / Work in Progress
● Other
motion operations
– motion cyclification.
– multiresolution filtering.
● New
techniques
– motion time-warping.
– motion/sound synchronization.
● Other
animation tools/techniques
– Inverse kinematics.
– Procedural.
Additional Info
http://www.visgraf.impa.br/Projects/mcapture
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