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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 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 Schematic drawing of the backbone Secondary Structure -Helices -Strands Random turns Tertiary Structure Folding -Sheets Computer Graphics, TU Braunschweig Information Visualisation 2004 4 Existing Tools – RasMol 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 Not passing through C-positions Moves C-positions to match ribbons Static Quality Computer Graphics, TU Braunschweig Information Visualisation 2004 6 Existing Tools – PyMol Passing through C-positions Static Quality No transition between different secondary structures types Computer Graphics, TU Braunschweig Information Visualisation 2004 7 Improvements Ribbons pass through C-positions Using multi-resolution approach Continuous transition between different secondary structure types Computer Graphics, TU Braunschweig Information Visualisation 2004 8 Combined BReps 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 9 Combined BReps Subdivision level is controlled by View frustum clipping Frame rate Projected size Curvature Contribution to the silhouette Computer Graphics, TU Braunschweig – – + + + Information Visualisation 2004 10 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 Computer Graphics, TU Braunschweig Information Visualisation 2004 11 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 Computer Graphics, TU Braunschweig Information Visualisation 2004 12 Building the Ribbon Structure Base mesh is generated by just joining the quads Arrows are very easy, too Using one base mesh smooth transition Computer Graphics, TU Braunschweig Information Visualisation 2004 13 Live Demo Demo Computer Graphics, TU Braunschweig Information Visualisation 2004 14 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/ Computer Graphics, TU Braunschweig Information Visualisation 2004 15 Thank you for your attention! Computer Graphics, TU Braunschweig Information Visualisation 2004 16