That's good to know. I'm happy taking the easy way out if it's not an huge difference, but it's nice to know that we could go there if need be.
On Nov 5, 2013 9:37 AM, "EBo" <[email protected]> wrote: > > It has been a very long time since I have needed to do curve fitting to > generic input date -- actually image2gcode processing + offset surfaces. > > If you extend the idea past pairs to replacing n-positions with either > a straight segment or arc, then a lot of these issues will either go > away or will be genuine problems. If they are in fact issues with the > geometry, then we should/could analyze the acceleration profile and > adjust the max velocity accordingly. > > EBo -- > > > On Nov 5 2013 7:23 AM, Robert Ellenberg wrote: > > Right now it will replace a pair of lines with a single arc if the > > blend > > tolerance allows it. > > > > I think the simplest answer is to slow the max velocity down so that > > it > > always hits every segment at least once. This will still be better > > than the > > current method unless the segment length is very small. > > > > One possibility is to increase the effective segment length by > > treating > > multiple tangent segments as one long segment, at least as far as the > > velocity profile is concerned. We would essentially be resampling the > > trajectory on the fly. > > > > -Rob > > > > On Nov 5, 2013 8:04 AM, "EBo" <[email protected]> wrote: > >> > >> On Nov 5 2013 5:38 AM, Gene Heskett wrote: > >> > On Tuesday 05 November 2013 07:37:15 andy pugh did opine: > >> > > >> >> On 5 November 2013 08:18, Robert Ellenberg <[email protected]> > >> wrote: > >> >> > 2. Sam's example has very short line segments (line lengths are > >> >> about > >> >> > > >> >> > 0.0001"). We're hitting the limits of the sampling rate when > >> >> > running this code. At 1kHz, to move faster than 0.1 in / sec > >> >> means > >> >> > we start skipping segments. > >> >> > >> >> That seems like pretty pathological G-code. If you can't even > >> >> "touch" > >> >> every segment at 1kHz at the requested speed then I don't think > >> you > >> >> should try to hold the speed. > >> > > >> > What Andy said. I am not in favor of throwing away accuracy. > >> > >> Are your approximating the little segments with arc's/splines and > >> reducing the complexity, or are you skipping over some of them. If > >> it > >> is the former, then you can set the approximation parameterization > >> and > >> know a priori exactly the behaviour. With line segments of only > >> 0.0001" > >> it is basically the equivalent of recording single/two steps on just > >> about any industrial machine tool. I mean, how many machine tools > >> to > >> you work with that resolve anything below 0.00005"? > >> > >> What I will say is that this is a great stress/regression test and > >> should be kept. We can continue to debate the appropriateness and > >> meaning of this pathological case. I for one say thank you for > >> taking > >> the test to the extreme. > >> > >> EBo -- > >> > >> > > > > ------------------------------------------------------------------------------ > >> November Webinars for C, C++, Fortran Developers > >> Accelerate application performance with scalable programming models. > > Explore > >> techniques for threading, error checking, porting, and tuning. Get > >> the > > most > >> from the latest Intel processors and coprocessors. 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