Some questions about Arc Welder

Hi, I am using Prusa i3MK3S+ with Octoprint 1.5.3. I just installed Arc Welder and got a couple of questions.

  1. As Arc Welder modified the original gcode from Prusa Slicer, the estimated printing time on Prusa Slicer 2.3 may be incorrect. How to get the most accurate estimate of the amount of time it takes to complete the print job and the remaining time?

  2. Even during the printing job, Print Time Left is "- :red_circle:" I cannot even get an estimate on how long it will take to complete the task. Is this a compatibility issue between the plugin and Octoprint?

  3. Is it possible to have a graphical view on how the 3D model looks like after modification of the gcode from Arc Welder? A side by side comparison with 3D manipulation would be great.


For the print time estimates, I would recommend using the PrintTimeGenius plugin - once you run a couple of prints through it, it will learn and adjust using it's simulation.

For the 3D model, there is the Pretty Gcode plugin that has arc support, so you can load it up in there. Not all slicers like arcs, I know Simplify 3D apparently does if you were to load it back in there, but that is expensive and other slicers have overtaken it in recent years.


Thanks. After I have completed the current print job, I will try that plugin.

Now I checked the Octoprint browser. It changed from "-:red_circle:" to 3 hours with print time 00:44. So Arc Welder added about 2 more hours of print time. Is this normal and the added time reasonable? I don't know if it could optimize the print to shorten the print time.

It shouldn't change the print time at all, unless your printer could not cope with small sections and had to slow down. I wouldn't put too much faith in OctoPrint's estimator, wait and see how long the print actually takes.

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I have the plugins you mentioned installed. In regard to Pretty Gcode, it shows the nozzle moving around the screen. Is this a real-time view? Can we look at how the entire model looks like before actual printing?

I tried a print with Arc Welder but it looks very ugly. The used to be smooth surface became very ugly rugged surface like having fish scales all over.

I wound up deleting pretty gcode. even on a Pi4 8GB running 2GHz CPU speed, pretty Gcode would display the part, and the travel etc were extremely slow in the plugin, then all of a sudden it would go into fast motion (like ridiculously fast) and catch up, then go back to slow and laggy, and repeat. used several different browsers, and my PC is no slouch. AMD Ryzen 9 3950X OC's to 4.1GHz, 32G DDR4 3600 RAM, 2 1TB M.2 drives, GEForce GTX2070 Graphics card with 8G RAM...

I noticed that when the extruder was moving in a straight line, it runs faster under pretty Gcode than in the video feed.

I tried Arc Welder a few times but it made lots of big winkles on the surface of my prints. I disabled it and tried again but the print still looked as if it Arc Welder were on. So I uninstalled the plugin and printed again. Same thing. Then, I saved the same file to a SD card and printed. The ugly winkle effect made by Arc Welder did not show up.

Why even I disabled and uninstalled the plugin, the ugly winkles were made? Did Arc Welder changed some settings in Octoprint? Is it better to reinstall Octoprint?

Could you show us a pic of those winkles?

Im running Pi4 8gb with Arc Welder, Pretty G-Code, Print Time Genius and many more plugins and i haven't ran into any issues with display, time, temps or anything really.

Using pretty g-code when you start your print and you goto pretty g-code it will catch up to the nozzle but you have to remember that its only listening to g-code actions and is not 100% real-time this is the same as the stock g-code viewer is actually ahead than the print as the signal that gets sent to the printer from octoprint is processed ahead in the mainboard memory.

I use cura latest for my slicer, not sure what's causing your issues.

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Some things to note that I have figured out which maybe of value when using Arc Welder:

  • Arc Welder modifies the G-Code - so even if you uninstall it, you'll need to use your slicer again to restore the G-Code (see next point).
  • Depending on your settings, Arc Welder can modify the file in place (this is not the default) - if you have done this, it's important to ensure the file is reloaded after the Gcode has been modified, I do this by opening another model, then clicking back. If you don't, the time remaining and GCode viewers get out of sync and do strange things.
  • If your print is having quality issues after using Arc Welder, it sounds like your printer firmware is not up to the job of generating the arcs on the fly. I use Klipper so all of the grunt work is done on the main controlling PC (not the micro-controller). If using Klipper, be sure to add a [gcode_arcs] section.
  • The Pretty GCode plugin relies on WebGL - so make sure WebGL is enabled with hardware acceleration support (this is becoming the default, but if the settings have ever been changed, it may not be for you). On my (very) old laptop, running an older version of Firefox, I had to enable it and hardware support. Once done, it works OK (it's not super smooth when rotating). On my normal laptop (a few years old now), it runs great on Firefox.
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Turns out it was a hardware problem with my printer. Apology to Arc Welder's developer.


Thanks. So Pretty GCode cannot take the gcode and make the graphical view of the entire print virtually before it is printed?

I checked ege://gpu
Under WebGL and WebGL2, they have "Hardware accelerated". However, Vulkan is Disabled by default. Is this OK?

Hi, when I launched the print job from Prussa Slicer, the browser connecting to Octoprint showed Arc Welder was doing something. However, when it is printing, under State, the file name is listed as filename.gcode Shouldn't it be How do I know if it is printing the original gcode or gcode modifed by Arc Welder?

The output file settings are:
Overwrite Source File: Enabled unchecked by default
Target File Postfix: aw
Print After Processing: Always
Select After Processing: Always

I would guess that in order to use slicer-based launching and Arc Welder you would need to set Arc Welder to overwrite.