looking for Post for FreeCAD path workbench

New Home Forum Software / Firmware Development looking for Post for FreeCAD path workbench

This topic contains 14 replies, has 2 voices, and was last updated by  Guffy 9 months, 2 weeks ago.

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  • #86918

    edwardvmills
    Participant

    I’ve had bad luck with long posts, so i’m going to split this into parts.

    from  https://www.freecadweb.org/wiki/Path_Post

    Included Postprocessors are saved in the FreeCAD.Mod.Path.Pathscripts.Post by default:

    • centroid
    • comparams
    • dynapath
    • grbl
    • linuxcnc
    • opensbp
    • phillips
    • rml
    • smoothie

    the grbl post seems to generate decent output, but i’m wary.

    the FreeCAD Path (CAM) workbench itself is pretty bomb. they have 2D adaptive, and 3d contour just around the corner. it is ready to roll for 2.5D, and i found it much more straightforward than fusion.

    Path_WB_Test_00_00

    using the grbl post i get decent looking repetier preview

     

    i did an air cut and it behaved basically correctly. but i can’t tell what the feeds are doing, and there was never a way to specify my rapids.

    i’m asking on the freecad forum at the same time…and if no one can talk me out of it 🙂 i might cut something

     

    #86920

    edwardvmills
    Participant

    repetier preview

    #86924

    edwardvmills
    Participant

    the gcode file output from FreeCAD with grbl post

    #86928

    edwardvmills
    Participant
    #86984

    edwardvmills
    Participant

    i just ended running the output of the GRBL post on a simple model, and it cut very nicely.

    #86986

    edwardvmills
    Participant

    tool editor doesn’t have as many options as fusion, but it’s serviceable. this is tool geometry only

    FreeCAD_Path_Setup_00_tool_library_editor

    #86989

    edwardvmills
    Participant

    separate tool controller sets feeds

     

    FreeCAD_Path_Setup_00_tool_controller_feeds

    #86992

    edwardvmills
    Participant

    setupsheet for planes, rapids, and the stepdown formula (editable, i add the ‘*.5’, default was full diameter stepdown)

    FreeCAD_Path_Setup_00_planes_stepdown_rapids

    #86995

    edwardvmills
    Participant

    overall job controls post processor

    FreeCAD_Path_Setup_00_post

    #86998

    edwardvmills
    Participant

    youtube videos for the FreeCAD Path workbench

    https://www.youtube.com/playlist?list=PLEuOia-QxyFJZSpqb0xOHc9t7MLdCO3io

     

    #87012

    Guffy
    Participant

    Gcode looks mostly acceptable to marlin. Except comments (?) and plane selection commands.

    But the way how post processing architected in freecam i don’t like. The input for a preprocessor is just “preparsed and decorated” gcode that already produced by freecad cam. So pp has to iterate that gcode and somehow change it. Better then raw text, but in general wrong way.

    In comparison with event based post processing architecture of Autodesk it’s just a toy.

    1 user thanked author for this post.
    #87083

    edwardvmills
    Participant

    Gcode looks mostly acceptable to marlin. Except comments (?) and plane selection commands.

    But the way how post processing architected in freecam i don’t like. The input for a preprocessor is just “preparsed and decorated” gcode that already produced by freecad cam. So pp has to iterate that gcode and somehow change it. Better then raw text, but in general wrong way.

    In comparison with event based post processing architecture of Autodesk it’s just a toy.

    of course the few guys coding the CAM side of FreeCAD in their spare time can’t truly compete with Autodesk, but i found it surprisingly usable.

    Fusion is great until Autodesk decides they don’t care about you 🙂 …they already sabotaged some plugins (or so it seems to me)…specifically because people were writing extensions that could eventually threaten the real cash cow, Vault (conjecture of course).

    i use Solidworks at work, but for hobby stuff, FreeCAD does a lot, and i feel like i own my own work.

    #87090

    Guffy
    Participant

    of course the few guys coding the CAM side of FreeCAD in their spare time can’t truly compete with Autodesk, but i found it surprisingly usable.

    You see, problem not only in how many coders and qa guys worked in Autodesk comparing to freecad team. Coding and testing are second and third part of developing sequence. First part is an idea and designing architecture.

    Guys from autodesk took architecture when cam core issues events that describes entities in domain notion – onLinear, onRapid, onCircular, onCycle, etc. Also there are a lot of current state objects –  current section, tool, spindle speed, cycle, etc. So, firstly, it’s easy to write post processor that generates whatever you want (as example there is pp which generates dxf). Secondary, developing pp is pretty comfortable task, pp core serve to you.

    Guys from freecad decided that they can use just tree of objects passed to pp, where each object is just a command from their superset gcode. So it’s like “preparsed stream”. So pp can just “hack” that stream – some commands can be dropped, some expanded like a macro – pp works as a filter. That means that some more complex task you will have to spend much more efforts.

    #87104

    edwardvmills
    Participant

    of course the few guys coding the CAM side of FreeCAD in their spare time can’t truly compete with Autodesk, but i found it surprisingly usable.

    You see, problem not only in how many coders and qa guys worked in Autodesk comparing to freecad team. Coding and testing are second and third part of developing sequence. First part is an idea and designing architecture.

    all very true. the difference with closed source, is here you could dig into wherever the ”CAM state and events” actually resides, put in your own hooks, and write a better PP architecture (should you ever ne possessed to do so). of course then you might not like how they do the CAM side of things either 🙂

    interesting tidbit: as some FreeCAD contributor was discussing his homebrew 2D adaptive, the actual original developer of adaptive jumped on and offered help and insight.

    as farf asaMPCNC/Marlin/FreeCAD right this very moment, i think the most practical thing is to get the PP to add rapid speed feed to G0, as they get spat out ‘naked’ right now. can you tell me more about the problems you see with planes? i am pretty much a total noob with gcode, but i am pretty good with 3D, python, PLCs, and robots.

     

    typed on mobile apologies for typos and style

     

    #87158

    Guffy
    Participant

    Freecad produce g17 command. It is selection of XY pane. (G18 xz, g19 yz. I don’t remember exactly). Afaik panes used to properly handle arc commands g2/g3.

    Marlin (and i guess all 3d-printer-like firmware) doesn’t support these gcodes because just doesn’t need to make arcs in panes other then xy.

    So just drop g17 (or may be marlin ignores it).

    Ensure that freecad doesn’t issue g18 and g19 with g2/g3. Such arcs will not work properly. If you will found you will have to write linearization code to replace such g2 with set of g1

    Check smoothie pp. Smoothie is mostly 3d printer firmware so maybe gcode will be better for marlin

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