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Graphite 2005
Texture for Volume Character
Animation
Peiyi Shen and Philip Willis
Media Technology Research Centre
Department of Computer Science
University of Bath
UK
http://www.bath.ac.uk/media/
Texture for Volume Character Animation
Introduction

New challenges and applications in
manipulating/animating/annotating
volume datasets.
STAR-EG2005 :
Deforming and Animating Discretely Sampled
Object Representations, State of the Art Report, Eurographics
‘05, Dublin, Ireland.
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Texture for Volume Character Animation
Introduction

Volume Datasets
- a collection of discrete samples
- no geometrical / topological /
semantic information
-> new challenges in deformation /
animation / annotation control
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Texture for Volume Character Animation
Introduction

Mesh texturing is well-advanced

Problems of mesh models?
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Dawn:

Curtis Beeson, Kevin Bjorke, Skin in the “Dawn” Demo,
Computer Graphics, Vol. 38, No. 2, 2004, pp 14-19.
Cubic map of environment; Diffuse colour map / bump map for
the front of the head; Vertex shader techniques.
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Skin(BSSRDF):
Henrik W. Jensen, Stephen R. Marschner,
Marc Levoy and Pat Hanrahan, A Practical Model for Subsurface Light
Transport, SIGGRAPH 2001.
Skin(Light-Diffusion):
C. Donner, H. W.
Jensen, Light Diffusion in Multi –Layered
Translucent Materials, SIGGRAPH 2005.
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Spherical Matching:
J. Starck, A. Hilton, Spherical
Matching for Temporal Correspondence of Non-Rigid Surface, ICCV 2005.

Spherical parameterisation
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Mesh Models:
Filling Holes in Complex
Surface using Volumetric
Diffusion [Ref1]
An Out-of-core Algorithm
for Isosurface Topology
Simplification [Ref2]
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Volume Animation:
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Texture for Volume Character Animation
Motivation

Our targets are:
1. To texture volume objects with realistic
appearance.
2. To develop a method which is robust
to topological artefacts
3. To use scalar-field based semantic
constraints to assist texture mapping
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Texture for Volume Character Animation
Functionality of our system

Plenoptic/cel texture +
projective indexing
+
semantic control
+
scalar field based volume environments: VLIB
(Andrew S. Winter: PhD thesis, Chapter 6, 2002,
University of Wales, Swansea)

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Plenoptic projection plus semantic constraints:
effectively a one-to-one parameterisation
texture mapping.
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Texture for Volume Character Animation
Texture Projection

Our system: the pipeline
(Left: after the style of Andrew S. Winter, with acknowledgements)
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Texture for Volume Character Animation
Texture Projection
Our system:
Plenoptic/cel texture + projective indexing + …
cylinder
sphere
cel
box
Texture primitives (Intermediate Template)
. .. ..
...
.
(Ox,Oy,Oz)
. .. ..
...
.
.

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P(u,v)
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Texture for Volume Character Animation
Constrained Rendering

Our system:
… + semantic constrained volume rendering.
(Ox,Oy,Oz)
P(u,v)
P(x,y)
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(Px,Py,Pz)
....
....
....
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Texture for Volume Character Animation
Semantic Constraints

Semantic constraints:
–
–
–

spatial
temporal
iso-surfaces etc
Applications:
–
–
–
annotation
illustration
and some more…
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Texture for Volume Character Animation
Semantic Constraints

Intermediate template
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Texture for Volume Character Animation
Semantic Constraints

Texture projective
mapping
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Texture for Volume Character Animation
Semantic Constraints

Volume visualisation
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Texture for Volume Character Animation
Semantic Constraints
Example 1: Semantic constraint
–
–
–
–
Surface texture model: spherical
Internal texture model: procedural model
Semantic information: distance field
Volume rendering engine: DVR
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Texture for Volume Character Animation
Texture Appliactions
Example 2: Multiple iso-surfaces

Volume rendering engine(DSR) will pick up
multiple iso-surfaces.
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Texture for Volume Character Animation
Texture Applications
Example 3:
Pseudo-solid
texture

An effective one-to-one
parameterisation texture
mapping.

Figures (a) and (b): DVR
Figures(c) and (d): DSR

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Texture for Volume Character Animation
Texture Applications
Example 4: Semantic constraint (1)

spatial transfer / semantic layers / volumetric sculpturing
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Texture for Volume Character Animation
Texture Applications
Example 5: Semantic constraint (2)

CVG operations / scalar fields functions – splitting
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Texture for Volume Character Animation
Texture Applications
Example 6: Semantic constraint (3)

Enhanced volume rendering engine
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Texture for Volume Character Animation
Texture Applications
Example 7: Semantic constraints(4)
Animation

Enhanced volume rendering engine: Animation apps.
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Texture for Volume Character Animation
Conclusions

System features:
– Volume Rendering Control
– 2D/2.5D/3D texture models
– Semantic constrained projective indexing: a practical
“one-to-one” texture mapping model.
– No mesh models, goes directly to volume datasets.
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Texture for Volume Character Animation
Acknowledgements


UK EPSRC funding the project
Project partners:
– University of Bath, UK
– Professor Min Chen, Dr Mark Jones, University of Wales, Swansea, UK
– Professor Deborah Silver The State University New Jersey, Rutgers, USA.

Special thanks to Dr Andrew S. Winter for supporting VLIB.

Ref:
Volume Animation Forum
http://www.cs.bath.ac.uk/van
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Texture for Volume Character Animation
Acknowledgements
Thank You
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Texture for Volume Character Animation
Refs.
[Ref1] J. Davis, S.R. Marschner, M. Garr, M. Levoy, Filling Holes in
Complex Surface using Volumetric Diffusion, Proc. 1st Int. Sym. On 3D
Data Processing, Visualization, Transmission. Padua, Italy, June 1921, 2002
[Ref2] Z. Wood, H. Hoppe, M. Desbrun, P. Schroder, An Out-of-core
Algorithm for Isosurface Topology Simplification, ACM Tran. On
Graphics, Vol.23, No.2, 2004, pp 190-208
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