Hi, I have this problem when switching from UltiGCode to Reprap style GCODE on my Ultimaker 2. It is sliced with Cura 15.04.03 with same settings I just changed the Gcode setting. Apart from holes being app. 0.2mm to small it looks like reprap codes doesnt draw circles but a series of small lines (I can haer a staggering sound when reprap code is drawing “circles” and a more continuos sound with UltiGCode).
The UltiGCode is executed from the SD card while the reprap is processsed from USB via Octoprint/Raspi.
Any ideas how to get the reprap style code perform like the UltiGcode (I would like to use Octoprint).
Difference is USB vs SD printing. Not UltiGCode vs None-UltiGCode.
Difference between UltiGCode and RepRap GCode is that start/end is handled by the machine, temperature is handled by the machine. And retraction length/speed is handled by the machine, as well as E values are in mm^3 instead of mm.
Pretty much by definition, even arc gcode is drawing a series of lines. The difference is how long the lines are. Printing from SD lets you issue many times more gcode commands per second without running out of bandwidth, so it’s plausible that a slicer that knows it’s printing via SD will chop curves into much-finer segments than one that knows it’s printing via USB. (And because of that difference, it’s possible that the reprap-style code has some automatic compensation for curve radii because otherwise you would uniformly come out wrong.)
@Kai_Laborenz I don’t know if it’s the fault of USB printing, OctoPrint, or your settings. But also could be a combination. I’ve done circles in USB printing just fine. But it can depend on the print speed.
@Kai_Laborenz Octoprint is a host. It will slice if you have the plugin but the function of the software is to control and monitor the printer. A host in and of itself won’t cause this.
Your gcode example of the smaller hole looks to be over extruded by quite a bit. The parameters that control extrusion are some of the parameters the ulticode gets from the machine. Particularly the volume and retraction settings. To test gcode slicing settings slow down the print speeds, reduce your extrusion multipler and adjust your retraction settings. Because some of the important settings are “baked in” to the machine when using ulticode, you’ll have to experiment and see which slicer settings work best when you have to control those parameters from gcode and not the machine.
@paul_wallich
arc g-codes draw lines in the resolution of the stepper motors because the machine control software does it, not the slicer. the code is 1 command (g2 or g3) for the entire arc.
I know of no slicer that can ready proper CAD file formats. They all only accept polygons. Since polygons can not describe a circle (only aproximate it), no slider should yet be able to ever output g2 or g3 unless the slicer is changing the geometry instead of interpreting it as it is given.
To me, this sound like the slicer is doing different things for Ultigcode and gcode. There should be no difference in printing from SD or USB. try #GcodeSimulator to see if the gcode looks as it should.
