From: Svend Tang-Petersen (svend++at++copen.sgi.com)
Date: 03/17/2000 08:17:49
Hi Vieri.
I was actually thinking about doing excately the same for
another project.
My approch was going to be the following:
1) obtain the min and max position values for x,y,z for the
full molecule.
2) generate an octree scenegraph for more efficient culling.
(I was actually thinking about further subdivision)
3) foreach loaded atom place it in the 8 or even 8x8 subgraphs
sorted by position
4) Foreach atom generate 3 maybe 4 LOD's to reduce the number of
polygons rendered.
It should be fairly simple.
Vieri Di Paola wrote:
>
> Hello performer-list,
>
> I am a Biology student and wish to make a simple program for viewing pdb
> molecules. As a small project, I would
> like some information on the following matter. My project consists in
> drawing spheres for each atom. My problem is that I cannot find any help
> anywhere on the Internet that explains an algorithm for efficient >15000
> spheres drawing. I suppose "hidden" spheres (according to a
> certain view angle) shouldn't be drawn, etc... Does IRIS-performer provide
> an efficient algorithm for the "spatial" model representation of
> molecules?
> Can anybody tell me exactly where to look at in the "performer" source
> code examples?
> Or can anybody tell me where (if) I can find a simple, to-the-point
> tutorial that handles this rendering problem?
>
> My project can be summarized as follows:
>
> 1- take a set of x,y,z atom coordinates from a pdb file (simple)
> 2- apply algorithm to "sort out" the atoms I need to draw according to the
> user's viewing angle
> 3- draw only the "visible" atoms by plotting spheres with the appropriate
> Wan Der Waals radius
> 4- update "visible" and "hidden" atoms when user rotates molecule
>
> I'm using FLTK (www.fltk.org) and MESA (www.mesa3d.org) (and hopefully
> Iris-performer) on Linux.
>
> Thanks in advance,
>
> Vieri Di Paola
>
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--Regards Svend
******************************************************************* Svend Tang-Petersen, MSc Email: svend++at++copen.sgi.com AGD, Europe Silicon Graphics Fax: (+45) 46579440 Hovedgaden 451 Phone: (+45) 46555660 2640 Hedehusene VNET: 540-0422 Denmark http://reality.sgi.com/svend_copen *******************************************************************
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