On Sat, Dec 21, 2013 at 9:48 AM, Clifford Yapp <[email protected]> wrote: > Wu, > > I've uploaded a comparison image of r5: > http://brlcad.org/~starseeker/r5_compare.png , with the above image > being the CSG raytrace and the below image being a shaded view of the > NURBS conversion (something's behaving funny with my raytracing > results for NURBS right now, so until I get that fixed the shaded view > is probably the better guide). The black lines in the latter are > indications that we have extra surfaces present that should have been > trimmed away, and there are some other indications of stray surfaces > if you compare the two images.
I've dug into this example a little further, and it turns out that rather than leaving extra faces behind, the extra surface area at the top of the model is a consequence of the coplanar subtractions never getting subtracted from the original surfaces. I'm not sure where it's failing, because individually converting s5 and s6 and doing intersections of the faces in question does produce correct trimming curves. Is the direction error (which appears to be resulting from the coplanarity of the intersections) depriving the subsequent algorithms of necessary information? The brep_boolean_tests.g in src/librt/tests has some tests for basic sphere/sphere boolean operations as well, which are giving surfaces with surprising UV space trimming behavior. A quick look by myself and Keith suggests that the presence of the sphere's degenerate edge may be causing some confusion - we would expect to see two half-circle trims on the top and bottom given the intersection topology, but instead we seem to get one circle in the middle of the UV space. No problem Wu if you're too busy with other stuff, but I thought I'd ask to see if these examples suggested anything to you. Thanks, CY ------------------------------------------------------------------------------ Rapidly troubleshoot problems before they affect your business. Most IT organizations don't have a clear picture of how application performance affects their revenue. With AppDynamics, you get 100% visibility into your Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics Pro! http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk _______________________________________________ BRL-CAD Developer mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/brlcad-devel
