Jump to content
UltiMaker Community of 3D Printing Experts

Some problem creating gCode from Python with cura engine and JSONfiles


simonst
 Share

Recommended Posts

Posted · Some problem creating gCode from Python with cura engine and JSONfiles

So after hours of painful forum post reading I managed to get a code running that lets me create a somewhat functioning gcode file. Idea of this project is to accelerate the whole workflow from .png image to 3D print: So my code takes an .png image, creates a greyscale mask of selected ROI, creates a .scad and .stl file with OpenSCAD and then by running the command:

command = [curaEngine, 'slice', '-j', myJSONfile, '-o', myGcode, '-l', mySTL] 

creates a gcode file.

 

The JSON file im inputting is a changed version of the anycubic_i3_mega_s.def.json file, where i add some settings like layer_height = 0.15 etc.

But for some reason i doesn't adjust all implemented changes: e.g. the skirt_brim_line_width is always 0.8mm when I check the gcode in ultimaker cura 4.11 although i specify it to be 0.4 (which is the Nozzle diameter) and it should be 0.4 by default anyway, as defined in the fdmprinter.def.json. The only brim setting it is applying is the brim_line_count somehow... I tried to look through the whole fdmprinter.def.json file which is inherited by myJSONfile to find a setting that might cause this issue, but couldn't figure it out. When i slice the created stl file with ultimaker cura 4.11 it works fine.

 

(Also for this whole process to work I had to save a copy of the inherited extruder json file to the same folder (/resources/definitions) as the printer file) 

 

If someone has some deeper knowledge on this topic i would be glad to hear from you. I attached the changed json file with all the overrides for the fdmprinter.def.json file and the output gcode file. The files it inherits can all be found in in the ultimaker installation folder (for me on windows:  Ultimaker/resources/definitions/)

 

code snippet that rewrites JSON files
#######################################################################################################
# Rewrite JSONfiles
#######################################################################################################


with open(JSONfile, 'r+') as f:
    data = json.load(f)
    data['overrides']["machine_start_gcode"]["default_value"] = "G21    ...
    
    data['overrides']["machine_end_gcode"]["default_value"] = "M104 S0  ....

                                 

    entry = {"layer_height": { "default_value": 0.15},


          "line_width": {"default_value": 0.4},

 

          "brim_width": {"default_value": 2.0},


          "skirt_brim_line_width": {"default_value": 0.4},

          "brim_line_count": {"default_value": 5},


          "adhesion_type": {"default_value": "brim"}}

 


    data["overrides"].update(entry)
    
### save copy to right folder
with open(savefile, 'w') as g: 
    g.seek(0)   
    json.dump(data, g, indent=4)
    

 

Question.zip

  • Link to post
    Share on other sites

    Posted · Some problem creating gCode from Python with cura engine and JSONfiles

    Only default_value is used by the engine. So if you set value to be "0.4" or "=some_other_setting", it will be ignored and default_value is used instead.

     

  • Link to post
    Share on other sites

    Posted · Some problem creating gCode from Python with cura engine and JSONfiles
    1 hour ago, nallath said:

    Only default_value is used by the engine. So if you set value to be "0.4" or "=some_other_setting", it will be ignored and default_value is used instead.

     

    Oh okay that's good to know! I was wondering if that is the case. but as you can see in the code snippet from my post above, I am only changing default_values, but e.g. skirt_brim_line_width = 0.4 (which should be the default anyway in fdmprinter.def.json) doesn't work somehow, while others work e.g. layer_height = 0.15.

  • Link to post
    Share on other sites

    Create an account or sign in to comment

    You need to be a member in order to leave a comment

    Create an account

    Sign up for a new account in our community. It's easy!

    Register a new account

    Sign in

    Already have an account? Sign in here.

    Sign In Now
     Share

    • Our picks

      • Here it is. The new UltiMaker S7
        The UltiMaker S7 is built on the success of the UltiMaker S5 and its design decisions were heavily based on feedback from customers.
         
         
        So what’s new?
        The obvious change is the S7’s height. It now includes an integrated Air Manager. This filters the exhaust air of every print and also improves build temperature stability. To further enclose the build chamber the S7 only has one magnetically latched door.
         
        The build stack has also been completely redesigned. A PEI-coated flexible steel build plate makes a big difference to productivity. Not only do you not need tools to pop a printed part off. But we also don’t recommend using or adhesion structures for UltiMaker materials (except PC, because...it’s PC). Along with that, 4 pins and 25 magnets make it easy to replace the flex plate perfectly – even with one hand.
         
        The re-engineered print head has an inductive sensor which reduces noise when probing the build plate. This effectively makes it much harder to not achieve a perfect first layer, improving overall print success. We also reversed the front fan direction (fewer plastic hairs, less maintenance), made the print core door magnets stronger, and add a sensor that helps avoid flooding.
         

         
        The UltiMaker S7 also includes quality of life improvements:
        Reliable bed tilt compensation (no more thumbscrews) 2.4 and 5 GHz Wi-Fi A 1080p camera (mounted higher for a better view) Compatibility with 280+ Marketplace materials Compatibility with S5 project files (no reslicing needed) And a whole lot more  
        Curious to see the S7 in action?
        We’re hosting a free tech demo on February 7.
        It will be live and you can ask any questions to our CTO, Miguel Calvo.
        Register here for the Webinar
          • Like
        • 10 replies
      • UltiMaker Cura 5.3.0-Alpha 🎄 Tree Support Spotlight 🎄
        Are you a fan of tree support, but dislike the removal process and the amount of filament it uses? Then we would like to invite you to try this special release of UltiMaker Cura. Brought to you by our special community contributor @thomasrahm
         
        We generated a special version of Cura 5.2 called 5.3.0 Alpha + Xmas. The only changes we introduced compared to UltiMaker Cura 5.2.1 are those which are needed for the new supports. So keep in mind, this is not a sneak peek for Cura 5.3 (there are some really cool new features coming up) but a spotlight release highlighting this new version of tree supports.  
          • Like
        • 16 replies
      • New here? Get ahead with a free onboarding course
        Hi,
         
        Often getting started is the most difficult part of any process. A good start sets you up for success and saves you time and energy that could be spent elsewhere. That is why we have a onboarding course ready for
        Ultimaker S5 Pro Bundle, Ultimaker S5, Ultimaker S3 Ultimaker 2+ Connect.   
        They're ready for you on the Ultimaker Academy platform. All you need to do to gain access is to register your product to gain free access. 
        Ready? Register your product here in just 60 seconds.
          • Like
        • 14 replies
    ×
    ×
    • Create New...