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Re: T-Junctions re-visited
March 20, 2013 06:42AM
Hi Travis,

I'm using a related technique: I have a single array of vertices, but they are sorted by a "lexicographal" comparison function (that is, sort by X, if X is equal sort by Y, if Y is equal, sort by Z, etc.).

This gives you similar performance times as the balanced binary tree - NlogN to get the index built (due to sort time) and log-time lookups via a binary search.

The big thing you lose with the array is cheap insertion of "more stuff." But in the case of my code, I know the total vertex count before I even start working (because I have the unsmoothed directive and can count up the triangles and quads and lines) so this is acceptable.

The other thing I discovered is that, given a vertex in the array, it is a bit faster to find the range of equal vertices by linear search (E.g. just walk in both directions in the array) than to do a binary search of the whole sorted array. I chalk this up to locality - more cache hits if the search stays close by. I've been meaning to do a 'step' search - that is, start in the array, walk in units of N vertices, then walk back by N/2, etc. If we start N at a small number like 16 or so, we can find groups of equal value vertices in only a few steps. But...performance profiles indicate that it's a small optimization at this point; the algorithm is currently dominated by the 'big sort' at the beginning.

I'm currently sorting the _entire_ part together -- lines and tris and quads. When I had the lines separate it was faster (it's quicker to sort two small things than one big thing) but I want to have one 'pile' of vertices for snapping things together, so I think one big pile it is.

I think the big win is going to be recursion optimizations, e.g. smooth the stud, recognize in the smoothing process that the stud is "sealed" from other parts and doesn't need to be resmoothed when it is included, then smooth the parent part without the studs. I base this on the fact that (1) my code can detect that the stud is sealed and (2) small parts optimize almost instantly and (3) the big baseplates minus studs have similar vertex counts to small parts. It's a big refactor to actually get the code working this way though; I'm going to finish T junction repair first.

Cheers
Ben
SubjectAuthorViewsPosted
T-Junctions re-visited Travis Cobbs665March 11, 2013 10:38PM
Re: T-Junctions re-visited Tim Gould313March 11, 2013 11:31PM
Re: T-Junctions re-visited Roland Melkert302March 12, 2013 11:17AM
Re: T-Junctions re-visited Ben Supnik303March 12, 2013 11:17AM
Re: T-Junctions re-visited Roland Melkert280March 12, 2013 11:22AM
Re: T-Junctions re-visited Ben Supnik284March 12, 2013 11:32AM
Re: T-Junctions re-visited Roland Melkert269March 12, 2013 11:41AM
Re: T-Junctions re-visited Ben Supnik286March 12, 2013 11:55AM
Re: T-Junctions re-visited Roland Melkert286March 13, 2013 10:08AM
Re: T-Junctions re-visited Travis Cobbs298March 13, 2013 11:27AM
Re: T-Junctions re-visited Allen Smith316March 12, 2013 02:01PM
Re: T-Junctions re-visited Michael Heidemann283March 13, 2013 09:27AM
Re: T-Junctions re-visited Ben Supnik284March 13, 2013 10:37AM
Re: T-Junctions re-visited Tim Gould280March 13, 2013 02:31PM
Re: T-Junctions re-visited Michael Heidemann274March 13, 2013 03:42PM
Re: T-Junctions re-visited Michael Heidemann283March 17, 2013 04:35AM
Re: T-Junctions re-visited Ben Supnik252March 17, 2013 08:43AM
Re: T-Junctions re-visited Michael Heidemann250March 17, 2013 08:59AM
Re: T-Junctions re-visited Ben Supnik258March 17, 2013 09:02AM
Re: T-Junctions re-visited Magnus Forsberg248March 17, 2013 09:15AM
Re: T-Junctions re-visited Travis Cobbs328March 17, 2013 10:09PM
Re: T-Junctions re-visited Ben Supnik281March 18, 2013 07:30AM
Re: T-Junctions re-visited Travis Cobbs291March 18, 2013 10:57AM
Re: T-Junctions re-visited Ben Supnik298March 18, 2013 11:27AM
Re: T-Junctions re-visited Travis Cobbs282March 18, 2013 12:23PM
Re: T-Junctions re-visited Ben Supnik301March 18, 2013 01:41PM
Re: T-Junctions re-visited Roland Melkert312March 18, 2013 02:51PM
Re: T-Junctions re-visited Travis Cobbs279March 18, 2013 02:59PM
Re: T-Junctions re-visited Roland Melkert326March 18, 2013 03:41PM
Re: T-Junctions re-visited Ben Supnik311March 18, 2013 06:09PM
Re: T-Junctions re-visited Roland Melkert301March 19, 2013 11:38AM
Re: T-Junctions re-visited Ben Supnik323March 19, 2013 11:43AM
Re: T-Junctions re-visited Roland Melkert333March 19, 2013 07:07PM
Re: T-Junctions re-visited Travis Cobbs310March 19, 2013 10:13PM
Re: T-Junctions re-visited Tim Gould292March 20, 2013 03:56AM
Re: T-Junctions re-visited Travis Cobbs284March 20, 2013 10:13AM
Re: T-Junctions re-visited Ben Supnik272March 20, 2013 10:23AM
Re: T-Junctions re-visited Travis Cobbs280March 20, 2013 10:29AM
Re: T-Junctions re-visited Travis Cobbs287March 20, 2013 10:26AM
Re: T-Junctions re-visited Ben Supnik267March 20, 2013 11:18AM
Re: T-Junctions re-visited Ben Supnik282March 20, 2013 06:42AM
Re: T-Junctions re-visited Roland Melkert273March 20, 2013 11:36AM
Re: T-Junctions re-visited Philippe Hurbain277March 20, 2013 06:36AM
Re: T-Junctions re-visited Ben Supnik301March 20, 2013 06:58AM
Re: T-Junctions re-visited Allen Smith299March 20, 2013 09:08AM
Re: T-Junctions re-visited Roland Melkert301March 20, 2013 11:35AM
Re: T-Junctions re-visited Ben Supnik700March 20, 2013 11:50AM
Re: T-Junctions re-visited Michael Heidemann300March 18, 2013 03:54PM
Re: T-Junctions re-visited Roland Melkert273March 13, 2013 10:03AM
Re: T-Junctions re-visited Tim Gould252March 13, 2013 03:56PM
Re: T-Junctions re-visited Sergio Reano263March 13, 2013 03:51PM
Re: T-Junctions re-visited Roland Melkert323March 13, 2013 04:36PM
Re: T-Junctions re-visited Tim Gould291March 13, 2013 05:10PM
Re: T-Junctions re-visited Ben Supnik275March 14, 2013 08:17PM
Re: T-Junctions re-visited Tim Gould338March 14, 2013 08:41PM
Re: T-Junctions re-visited Ben Supnik331March 15, 2013 10:56AM
Re: T-Junctions re-visited Roland Melkert281March 15, 2013 11:36AM
Re: T-Junctions re-visited Ben Supnik252March 13, 2013 06:58PM
Re: T-Junctions re-visited Roland Melkert267March 13, 2013 07:27PM
Re: T-Junctions re-visited Ben Supnik245March 13, 2013 07:37PM
Re: T-Junctions re-visited Roland Melkert265March 13, 2013 07:59PM
Re: T-Junctions re-visited Ben Supnik293March 13, 2013 08:18PM
Re: T-Junctions re-visited Travis Cobbs311March 14, 2013 03:23PM
Re: T-Junctions re-visited Roland Melkert327March 14, 2013 03:34PM
Re: T-Junctions re-visited Tim Gould340March 14, 2013 03:41PM
Re: T-Junctions re-visited Roland Melkert309March 15, 2013 11:33AM
Re: T-Junctions re-visited Tim Gould268March 13, 2013 07:43PM
Re: T-Junctions re-visited Roland Melkert260March 13, 2013 08:08PM
Re: T-Junctions re-visited Tim Gould265March 13, 2013 08:18PM
Re: T-Junctions re-visited Ben Supnik330March 14, 2013 08:15PM
Re: T-Junctions re-visited Roland Melkert323March 15, 2013 11:29AM
Re: T-Junctions re-visited Travis Cobbs291March 15, 2013 12:27PM
Re: T-Junctions re-visited Ben Supnik312March 15, 2013 05:08PM
Re: T-Junctions re-visited Travis Cobbs299March 16, 2013 11:29PM
Re: T-Junctions re-visited Ben Supnik247March 17, 2013 08:58AM
Re: T-Junctions re-visited Roland Melkert251March 17, 2013 12:35PM
Re: T-Junctions re-visited Travis Cobbs280March 18, 2013 12:28PM
Re: T-Junctions re-visited Travis Cobbs316March 18, 2013 12:32PM
Re: T-Junctions re-visited Roland Melkert290March 18, 2013 05:00PM
Re: T-Junctions re-visited Travis Cobbs328March 18, 2013 11:05PM
Re: T-Junctions re-visited Roland Melkert346March 19, 2013 11:38AM
Re: T-Junctions re-visited Sergio Reano333March 26, 2013 02:46PM
Re: T-Junctions re-visited Roland Melkert279March 27, 2013 11:19AM
Re: T-Junctions re-visited Sergio Reano333March 27, 2013 01:48PM



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