On Jun 3, 2009, at 8:58 AM, Tom Browder wrote: > Any predictions as to when it may be usable or at least ready for > user testing?
Hopefully by the end of summer we'll have CSG boolean evaluation complete, that's the hardest step. After that, we'll need spline surface tessellation (which is relatively simple) and then facetized exports will be feasible through a more robust approach. The project to watch there is the progress of Joe Doliner and his GSoC summer project. That said, I wouldn't expect practical user testing until late in the calendar year at best as it'll take a while to integrate an exporter usefully for testing and visualization purposes. > I don't see that they are changed after the initial selection--I > probably missed something. I notice that in g-xxx_facets.c there is > still a comment: > > /* Set up calculation tolerance defaults */ > /* XXX These need to be improved */ Only the Pro/E export plugin uses the dynamic tessellation approach, which isn't a g-*.c exporter. It's in src/external as it links to commercial Pro/E libs. The basic idea, though, is like setting the calculation tolerance defaults like you found, but then refining them for objects that fail. > Do you know of any study of the effects of the various tolerances? Mm, not sure what you mean but the answer is probably "no". The manpage for g-iges probably explains the four tolerance values the best. The four work in harmony together, but the absolute tolerance is usually the dominant factor. > I'll try to clean it up and do that. Awesome. > So I suppose the new technique wouldn't help such degenerate geometry. Depending on how invalid the geometry is, probably not. It's really case by case though and is something that is generally interactively "geometrically debugged" during import. There's a whole industry of "mesh healing tools" that some companies focus on providing, pretty tricky stuff with lots of guesswork and failure recovery. It's often easier to just import the geometry into a mesher tool (e.g. Blender, Geomagic, etc), do the repairs, export, then do the import. > One more question: if you were going to pick the cleanest and > clearest of the g-*.c files as a template for converting a BRL-CAD db > to faceted geometry, what would be your choice? Depends whether you want simple or better. :-) Generally, the newer the better as each new converter seems to incorporate something slightly better than a predecessor. The facets example is pretty good and a nice "empty template". The dxf exporter is one of the most well-developed. The new 'bot_dump' command is also worth a look in terms of exporting BoT meshes. If what you have is already a BoT, then bot_dump will export it without attempting to validate the geometry for closure, correctness, etc. It'll just dump it to a given format. Only relevant for bad meshes that are already imported and in BoT (or NMG with a little work) format. > P.S. I know I still owe a promised effort to rename the plot files > from ,pl to something else. I may have to put that off until > retirement (which may not be too long). You retire?! Oh noes! Cheers! Sean ------------------------------------------------------------------------------ OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get _______________________________________________ BRL-CAD Developer mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/brlcad-devel
