Is the one-line lookahead statement also true blended paths? And how does it apply to splines? I find all this quite surprising, even grbl does lookahead over all the lines in the buffer (and hence has a latency while trying to pause or stop)
Does somebody know if this diagram is whats linuxcnc does, or if its just a proposal: http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Trapezoidal_Velocity_Profile_Trajectory_Planner Are there any good theoretical books about trajectory planning/step generation that somebody could recommend (non-popular, hardcore numerics preferred)? Arc fitting is not very easy it seems. Of all the reprap slicers, only slic3r can create arcs by looking for repetitive segments of same length and connecting at similar angles . The problem is that the 3d object itself is defined as stl files, and hence exists only as small patches of lines after slicing. And I know of no pcb isolation milling software that creates fitted arcs (while tracing lines in a 300dpi image). There are a couple of algorithms for finding the arc, if you know that some points are supposed to be on an arc. The problem starts when trying to decide, where arcs start and where they stop optimally. very nice greetings, Bernhard On 3/19/2012 4:30 AM, Youda He wrote: > This is very interesting, we are planning to.start using linuxcnc some time > in near future. We mainly mill organic shapes, such as 3DProcessing scanned > head models, the models start as mesh stl models with million a of small > triangles we would like to mill at fastest possible speed and can tolerate > some error in precision. Do we need to insert g64 on start, or is it by > default start in maximum speed mode. or is Mack3 in this case is a better > solution? > On Mar 18, 2012 7:21 PM, "Steve Blackmore"<st...@pilotltd.net> wrote: > >> On Sat, 17 Mar 2012 17:28:05 +0100, you wrote: >> >> >>> My assumption about Tarjectory planning was based on Anders Wallins >>> message as he mentioned some problem with limited look-ahead, >>> I suppose this affects the shape of the calculated path in some cases? >> Effectively LinuxCNC only looks ahead one line. >> >> > From my experience with 2.4.6 it's poor on arc to line or line to arc >> moves using a parallel port setup with steppers. It's very jerky >> compared to Mach3 with the same settings. >> >> Steve Blackmore >> -- >> >> >> ------------------------------------------------------------------------------ >> 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 >> Emc-users@lists.sourceforge.net >> 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 > Emc-users@lists.sourceforge.net > 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
