“ Visualization of Complex Molecular Ribbon Structures at Interactive Rates ”

Information Visualisation 2004 1Computer Graphics, TU Braunschweig

“Visualization of Complex Molecular Ribbon

Structures at Interactive Rates”

Andreas Halm, Lars Offen, Dieter Fellner (TU Braunschweig)

8th International ConferenceInformation Visualisation 2004


Overview

What are ribbon structures? Existing tools Improvements

Representation based on Combined BReps Dynamic Tessellation

Live Demo


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


Ribbon Structures

Schematic drawing of the backbone

Secondary Structure -Helices -Strands Random turns

Tertiary Structure Folding -Sheets


Existing Tools – RasMol Not passing through

C-positions Static, low Quality No transition between

different secondary structure types


Existing Tools – Chimera

Not passing through

C-positions Moves C-positions

to match ribbons Static Quality


Existing Tools – PyMol Passing through

C-positions Static Quality No transition

between different secondary structures types


Improvements

Ribbons pass through C-positions

Using multi-resolution approach

Continuous transition between different secondary structure types


Combined BReps

Combination of polygonal BBoundary

RepRepresentation Catmull/Clark Subdivision Surfaces Sharpness flag for each edge

sharp facesmooth face

crease edge


Combined BReps

Subdivision level is controlled by View frustum clipping – Frame rate – Projected size + Curvature + Contribution to the silhouette +


Spline Interpolation

Underlying structure of a ribbon is a B-spline curve

given: C-positions

desired: control points

done by solving a system of linear equations, derived from a decomposition into Bézier segments


Building the Ribbon Structure

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


Building the Ribbon Structure

Base mesh is generated by just joining the quads

Arrows are very easy, too

Using one base mesh smooth transition


Live Demo

Demo


References

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/


Thank you for your attention!

“ Visualization of Complex Molecular Ribbon Structures at Interactive Rates ”

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