Transcript lo-IV04-RibbonStructures

8th International Conference
Information Visualisation 2004
“Visualization of Complex
Molecular Ribbon
Structures at Interactive
Rates”
Andreas Halm, Lars Offen, Dieter Fellner
(TU Braunschweig)
Computer Graphics,
TU Braunschweig
Information Visualisation 2004
1
Overview
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What are ribbon structures?
Existing tools
Improvements
 Representation based on Combined BReps
 Dynamic Tessellation
Live Demo
Computer Graphics,
TU Braunschweig
Information Visualisation 2004
2
Credit
Ribbon Visualization results from the
collaboration project BioBrowser (funded by the
German Research Foundation, DFG) between
the
 Institute of Computer Graphics,
TU Braunschweig and
 Structural Biology,
Ges. f. Biotechnologische Forschung (GBF),
D. Heinz, G. Dieterich, J. Reichelt
Computer Graphics,
TU Braunschweig
Information Visualisation 2004
3
Ribbon Structures
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Schematic drawing
of the backbone
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Secondary Structure
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-Helices
-Strands
Random turns
Tertiary Structure
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Folding
-Sheets
Computer Graphics,
TU Braunschweig
Information Visualisation 2004
4
Existing Tools – RasMol
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Not passing through
C-positions
Static, low Quality
No transition between
different secondary
structure types
Computer Graphics,
TU Braunschweig
Information Visualisation 2004
5
Existing Tools – Chimera
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Not passing through
C-positions
Moves C-positions
to match ribbons
Static Quality
Computer Graphics,
TU Braunschweig
Information Visualisation 2004
6
Existing Tools – PyMol
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Passing through
C-positions
Static Quality
No transition
between different
secondary
structures types
Computer Graphics,
TU Braunschweig
Information Visualisation 2004
7
Improvements
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Ribbons pass through C-positions
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Using multi-resolution approach
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Continuous transition between different
secondary structure types
Computer Graphics,
TU Braunschweig
Information Visualisation 2004
8
Combined BReps
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Combination of
polygonal Boundary
Representation
 Catmull/Clark
Subdivision Surfaces
 Sharpness flag for
each edge

smooth face
crease edge
Computer Graphics,
TU Braunschweig
sharp face
Information Visualisation 2004
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Combined BReps
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Subdivision level is controlled by
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View frustum clipping
Frame rate
Projected size
Curvature
Contribution to the silhouette
Computer Graphics,
TU Braunschweig
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–
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Information Visualisation 2004
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Spline Interpolation
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Underlying structure of a ribbon is a B-spline
curve
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given: C-positions
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desired:
control points
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done by solving a system of linear equations,
derived from a decomposition into Bézier
segments
Computer Graphics,
TU Braunschweig
Information Visualisation 2004
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Building the Ribbon Structure
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The structure of an
amino acid
determines the quad
for each C
Each quad is normal
to the tangent of the
B-Spline curve in C
To avoid twisted
ribbons re-labeling
may occur
Computer Graphics,
TU Braunschweig
Information Visualisation 2004
12
Building the Ribbon Structure
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Base mesh is
generated by just
joining the quads
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Arrows are very
easy, too
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Using one base mesh
 smooth transition
Computer Graphics,
TU Braunschweig
Information Visualisation 2004
13
Live Demo
Demo
Computer Graphics,
TU Braunschweig
Information Visualisation 2004
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References
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J.Richardson. The anatomy and taxonomy of
protein structure. Adv. Protein Chem.,
pages 167-339, 1981.
RasMol: http://www.rasmol.org
Chimera: http://www.cgl.ucsf.edu/chimera/
PyMol: http://pymol.sourceforge.net/
Computer Graphics,
TU Braunschweig
Information Visualisation 2004
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Thank you for your attention!
Computer Graphics,
TU Braunschweig
Information Visualisation 2004
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