I ran into a problem with following errors if a move is exactly along a triangle edge
I havent investigated it further but I guess it could be a discontinuity/numerical accuracy/stability problem along the edges If that is the case, the approach using discrete-triangle based correction could be fundamentally flawed one way I guess would work is to create a continuous surface correction function, like a cubic spline - Michael Am 19.03.2012 um 21:03 schrieb Fox Mulder: > Since the last mail from december it has gotten really quite about this > very handy feature. But i can see in the git logs that it was further > developed. > > So what is the state of it right now and how could it be used? > > Sadly i can't find any info at all on the linuxcnc website. > I want to do some pcb etching tests in the next few weeks and i think > this feature would be a great benefit for this purpose. :) > > Ciao, > Rainer > > Am 21.12.2011 08:31, schrieb Michael Haberler: >> I found the idea quite intriguing, and thought about integrating the surface >> correction idea better. After bouncing a few ideas with Andy, this is what I >> have so far: >> >> probekins: a kinematics module which be default behaves like trivkins >> it accepts a mesh of triangles which define Z correction values (actually an >> approximation of the workpiece surface, or machine surface for that matter) >> >> this mesh might eventually generated by probing, but also used as a general >> machine Z correction >> >> >> this isnt finished or polished, but I'm posting it anyway to see what folks >> think about it. >> >> see http://git.mah.priv.at/gitweb/emc2-dev.git/shortlog/refs/heads/probekins >> >> - Michael >> >> -------- >> >> >> >> v0.1 README: >> >> Z correction by triangular mesh >> ------------------------------- >> >> The probekins kins module is a trivial kinematics module unless loaded with >> a Z correction mesh. >> >> It helps dealing with warped workpiece surfaces (or machines), and was >> inspired by a recent thread on emc-users about PCB milling. >> >> the correction mesh is a set of triangles specified by an STL file. This >> file might eventually be generated by probing a few points, >> and creating a triangular mesh from it, for instance by a Delauney >> triangulation, >> >> If a point (x,y) lies within the one of the triangles, it's z value is >> adjusted by the interpolated value on the enclosing triangle. >> Points outside any triangle are not corrected for. This means the correction >> value currently 'falls off the cliff' at the convex hull of the >> triangles (the enclosing polygon if you will). >> >> The triangles are applied in the order specified in the file, so there could >> be a 'later' larger triangle enclosing or overlapping >> an earlier one. >> >> The algorithm currently is based on a brute-force test of all triangles >> until first match. >> The ray/triangle intersection test is very fast, nevertheless this is an >> O(number of triangles) implementation. >> There are numerous ways to optimize this which are left as an exercise for >> the reader;). >> >> To load an STL Z correction file: >> --------------------------------- >> python stlcorr.py <file,stl> >> >> To inspect the current correction: >> ---------------------------------- >> python stlcorr.py >> >> To clear the correction: >> ------------------------ >> python stlcorr.py -c >> >> >> >> >> Example STL file containing two triangles: >> -------------------- >> solid >> facet normal 0 1 1 >> outer loop >> vertex 0 0 0 >> vertex 0 5 0 >> vertex 5 0 2 >> endloop >> endfacet >> facet normal 2 3 4 >> outer loop >> vertex 1 1 1 >> vertex -1 -1 1 >> vertex 1 -1 2 >> endloop >> endfacet >> endsolid >> ----------------- >> The normal vectors are ignored and can be left out for the purpose of >> describing a correction mesh. > > ------------------------------------------------------------------------------ > This SF email is sponsosred by: > Try Windows Azure free for 90 days Click Here > http://p.sf.net/sfu/sfd2d-msazure > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ This SF email is sponsosred by: Try Windows Azure free for 90 days Click Here http://p.sf.net/sfu/sfd2d-msazure _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
