If you do a google for ' osg simplfy' you will see a few hits such as http://www.openscenegraph.org/documentation/OpenSceneGraphReferenceDocs/a00677.html
I believe this uses edge collapse algorithm . This should give you an example of how you could port your own work and see how they compare etc ______________________________________________________________________________ Gordon Tomlinson www.photographybyGordon.com www.gordontomlinson.com www.vis-sim.com "Self defence is not a function of learning tricks but is a function of how quickly and intensely one can arouse one's instinct for survival" -Master Tambo Tetsura -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Jörg Bachmann Sent: Saturday, March 12, 2011 2:15 PM To: [email protected] Subject: [osg-submissions] Mesh Simplification Hi, until one week ago, i have writte a small library (C++) to simplify meshes! today i learned to know about osg (took me ~5 hours to complete all tutorials) and i really like it. i saw, that there is a LOD class and i saw this thread: http://forum.openscenegraph.org/viewtopic.php?t=3699 i think, what he was asking for is not lod itselfes, but for techniques to simplify meshes, which told me that there are no meshsimplification algorithms implemented in osg.(? <- 1st/2 question) iff that's the case, i'd try to port my meshsimplification lib to a plugin or something similar, but possibly i'm not familiar enough with osg, to see where to start. that's why i would ask for some help to "port" my classes to osg. i implemented a flexible interface to use different (pluggable) simplification approaches (all based on edge-collapses) and collapsing-functions (choice of coordinates for vertex of collapsed edge). so far, i have the following implementations, which produce really nice results. simplification approaches: - sth. like polychob by s.melax (based on normal errors) - garland & heckberts quadrics errors (based on geometric errors) - approach to avoid mesh degeneration (simple math, own idea, only meaningful in combination with one of the other) - one approach which simply summarizes them (weighted sum of the above mentioned / like hoppe) collapsing-functions: - choose midpoint - choose weighted midpoint (on edge), based on areas of surrounding triangles nevertheless, the "library" has some benefits: - own mesh class, to handle simplification (need a lot of cross referencing lists... list<triangles>, list<edges>, list<verts>) - triangle handling only - not sure about licenses of garland & heckbert / melax well. then there is one last question: LOD only hops between levels (of details). i also wrote a derivative, which interpolates between levels to not see jumps in graphics. would it be possible to get that working efficiently and elegant in osg? best regards, jörg _______________________________________________ osg-submissions mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org _______________________________________________ osg-submissions mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org
