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IDProjectCategoryView StatusLast Update
0004320PathFeaturepublic2020-10-07 18:16
Reportersliptonic Assigned Tosliptonic  
PrioritynormalSeverityminorReproducibilityN/A
Status assignedResolutionopen 
Product Version0.19 
Target Version0.20 
Summary0004320: Support incremental Gcode in postprocessors
DescriptionSome machine controls require gcode to be incrmental. We currently don't have any postprocessors that work this way so there's no reference implementation.

https://forum.freecadweb.org/viewtopic.php?f=15&t=44554&p=380569&hilit=edm#p380569
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sliptonic

2020-04-22 22:48

manager   ~0014366

I really need a sample file and gcode to work with but here's an early attempt to try.

I made a 10x10 cube and profiled it without compensation. Use the attached postprocessor with the following parameters
--no-header --relative --axis-modal --line-numbers

The output looks like this:

N105 (begin preamble)
N110 G17 G54 G40 G49 G80 G91
N115 G91
N120 G21
N125 (begin operation: Fixture)
N130 (machine: not set, mm/min)
N135 G54
N140 (finish operation: Fixture)
N145 (begin operation: Spot Drill001)
N150 (machine: not set, mm/min)
N155 (Spot Drill001)
N160 M5
N165 M6 T2
G43 H2
N170 M3 S0
N175 (finish operation: Spot Drill001)
N180 (begin operation: Contour)
N185 (machine: not set, mm/min)
N190 (Contour)
N195 (Uncompensated Tool Path)
N200 G0 Z+016000
N205 G0 X+005000 Y+005000
N210 G0 Z-002000
N215 G1 Z-014000
N220 G1 Y-010000
N225 G1 X-010000
N230 G1 Y+010000
N235 G1 X+010000
N240 G0 Z+016000
N245 (finish operation: Contour)
(begin postamble)
N250 M05
N255 G17 G54 G90 G80 G40
N260 M2
relative_post.py (16,164 bytes)   
# ***************************************************************************
# *   (c) sliptonic (shopinthewoods@gmail.com) 2014                        *
# *                                                                         *
# *   This file is part of the FreeCAD CAx development system.              *
# *                                                                         *
# *   This program is free software; you can redistribute it and/or modify  *
# *   it under the terms of the GNU Lesser General Public License (LGPL)    *
# *   as published by the Free Software Foundation; either version 2 of     *
# *   the License, or (at your option) any later version.                   *
# *   for detail see the LICENCE text file.                                 *
# *                                                                         *
# *   FreeCAD is distributed in the hope that it will be useful,            *
# *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
# *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
# *   GNU Lesser General Public License for more details.                   *
# *                                                                         *
# *   You should have received a copy of the GNU Library General Public     *
# *   License along with FreeCAD; if not, write to the Free Software        *
# *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  *
# *   USA                                                                   *
# *                                                                         *
# ***************************************************************************/
from __future__ import print_function
import FreeCAD
from FreeCAD import Units
import Path
import argparse
import datetime
import shlex
import math
from PathScripts import PostUtils
from PathScripts import PathUtils

TOOLTIP = '''
This is a postprocessor file for the Path workbench. It is used to
take a pseudo-gcode fragment outputted by a Path object, and output
real GCode suitable for a linuxcnc 3 axis mill. This postprocessor, once placed
in the appropriate PathScripts folder, can be used directly from inside
FreeCAD, via the GUI importer or via python scripts with:

import linuxcnc_post
linuxcnc_post.export(object,"/path/to/file.ncc","")
'''

now = datetime.datetime.now()

parser = argparse.ArgumentParser(prog='linuxcnc', add_help=False)
parser.add_argument('--no-header', action='store_true', help='suppress header output')
parser.add_argument('--no-comments', action='store_true', help='suppress comment output')
parser.add_argument('--line-numbers', action='store_true', help='prefix with line numbers')
parser.add_argument('--no-show-editor', action='store_true', help='don\'t pop up editor before writing output')
parser.add_argument('--precision', default='3', help='number of digits of precision, default=3')
parser.add_argument('--preamble', help='set commands to be issued before the first command, default="G17\nG90"')
parser.add_argument('--postamble', help='set commands to be issued after the last command, default="M05\nG17 G90\nM2"')
parser.add_argument('--inches', action='store_true', help='Convert output for US imperial mode (G20)')
parser.add_argument('--modal', action='store_true', help='Output the Same G-command Name USE NonModal Mode')
parser.add_argument('--axis-modal', action='store_true', help='Output the Same Axis Value Mode')
parser.add_argument('--no-tlo', action='store_true', help='suppress tool length offset (G43) following tool changes')
parser.add_argument('--relative', action='store_true', help='Generate Relative GCODE')

TOOLTIP_ARGS = parser.format_help()

# These globals set common customization preferences
OUTPUT_COMMENTS = True
OUTPUT_HEADER = True
OUTPUT_LINE_NUMBERS = False
SHOW_EDITOR = True
MODAL = False  # if true commands are suppressed if the same as previous line.
USE_TLO = True # if true G43 will be output following tool changes
OUTPUT_DOUBLES = True  # if false duplicate axis values are suppressed if the same as previous line.
COMMAND_SPACE = " "
LINENR = 100  # line number starting value
RELATIVE_GCODE = False

# These globals will be reflected in the Machine configuration of the project
UNITS = "G21"  # G21 for metric, G20 for us standard
UNIT_SPEED_FORMAT = 'mm/min'
UNIT_FORMAT = 'mm'

MACHINE_NAME = "Gegs Wire EDM"
CORNER_MIN = {'x': 0, 'y': 0, 'z': 0}
CORNER_MAX = {'x': 500, 'y': 300, 'z': 300}
PRECISION = 3

# Preamble text will appear at the beginning of the GCODE output file.
PREAMBLE = '''G17 G54 G40 G49 G80 G91
'''

# Postamble text will appear following the last operation.
POSTAMBLE = '''M05
G17 G54 G90 G80 G40
M2
'''

# Pre operation text will be inserted before every operation
PRE_OPERATION = ''''''

# Post operation text will be inserted after every operation
POST_OPERATION = ''''''

# Tool Change commands will be inserted before a tool change
TOOL_CHANGE = ''''''

# to distinguish python built-in open function from the one declared below
if open.__module__ in ['__builtin__','io']:
    pythonopen = open


def processArguments(argstring):
    # pylint: disable=global-statement
    global OUTPUT_HEADER
    global OUTPUT_COMMENTS
    global OUTPUT_LINE_NUMBERS
    global SHOW_EDITOR
    global PRECISION
    global PREAMBLE
    global POSTAMBLE
    global UNITS
    global UNIT_SPEED_FORMAT
    global UNIT_FORMAT
    global MODAL
    global USE_TLO
    global OUTPUT_DOUBLES
    global LOCATION # keep track for no doubles
    global RELATIVE_GCODE

    try:
        args = parser.parse_args(shlex.split(argstring))
        if args.no_header:
            OUTPUT_HEADER = False
        if args.no_comments:
            OUTPUT_COMMENTS = False
        if args.line_numbers:
            OUTPUT_LINE_NUMBERS = True
        if args.no_show_editor:
            SHOW_EDITOR = False
        print("Show editor = %d" % SHOW_EDITOR)
        PRECISION = args.precision
        if args.preamble is not None:
            PREAMBLE = args.preamble
        if args.postamble is not None:
            POSTAMBLE = args.postamble
        if args.inches:
            UNITS = 'G20'
            UNIT_SPEED_FORMAT = 'in/min'
            UNIT_FORMAT = 'in'
            PRECISION = 4
        if args.modal:
            MODAL = True
        if args.no_tlo:
            USE_TLO = False
        if args.axis_modal:
            OUTPUT_DOUBLES = False
        if args.relative:
            print ('relative')
            RELATIVE_GCODE = True
            PREAMBLE = PREAMBLE + " G91"
            LOCATION = {'X':0, 'Y':0, 'Z':0}

    except Exception: # pylint: disable=broad-except
        print(Exception)
        return False

    return True

def export(objectslist, filename, argstring):
    # pylint: disable=global-statement
    if not processArguments(argstring):
        return None
    global UNITS
    global UNIT_FORMAT
    global UNIT_SPEED_FORMAT

    for obj in objectslist:
        if not hasattr(obj, "Path"):
            print("the object " + obj.Name + " is not a path. Please select only path and Compounds.")
            return None

    print("postprocessing...")
    gcode = ""

    # write header
    if OUTPUT_HEADER:
        gcode += linenumber() + "(Exported by FreeCAD)\n"
        gcode += linenumber() + "(Post Processor: " + __name__ + ")\n"
        gcode += linenumber() + "(Output Time:" + str(now) + ")\n"

    # Write the preamble
    if OUTPUT_COMMENTS:
        gcode += linenumber() + "(begin preamble)\n"
    for line in PREAMBLE.splitlines(False):
        gcode += linenumber() + line + "\n"
    gcode += linenumber() + UNITS + "\n"

    for obj in objectslist:

        # Skip inactive operations
        if hasattr(obj, 'Active'):
            if not obj.Active:
                continue
        if hasattr(obj, 'Base') and hasattr(obj.Base, 'Active'):
            if not obj.Base.Active:
                continue

        # fetch machine details
        job = PathUtils.findParentJob(obj)

        myMachine = 'not set'

        if hasattr(job, "MachineName"):
            myMachine = job.MachineName

        if hasattr(job, "MachineUnits"):
            if job.MachineUnits == "Metric":
                UNITS = "G21"
                UNIT_FORMAT = 'mm'
                UNIT_SPEED_FORMAT = 'mm/min'
            else:
                UNITS = "G20"
                UNIT_FORMAT = 'in'
                UNIT_SPEED_FORMAT = 'in/min'

        # do the pre_op
        if OUTPUT_COMMENTS:
            gcode += linenumber() + "(begin operation: %s)\n" % obj.Label
            gcode += linenumber() + "(machine: %s, %s)\n" % (myMachine, UNIT_SPEED_FORMAT)
        for line in PRE_OPERATION.splitlines(True):
            gcode += linenumber() + line

        # get coolant mode
        coolantMode = 'None'
        if hasattr(obj, "CoolantMode") or hasattr(obj, 'Base') and  hasattr(obj.Base, "CoolantMode"):
            if hasattr(obj, "CoolantMode"):
                coolantMode = obj.CoolantMode
            else:
                coolantMode = obj.Base.CoolantMode

        # turn coolant on if required
        if OUTPUT_COMMENTS:
            if not coolantMode == 'None':
                gcode += linenumber() + '(Coolant On:' + coolantMode + ')\n'
        if coolantMode == 'Flood':
            gcode  += linenumber() + 'M8' + '\n'
        if coolantMode == 'Mist':
            gcode += linenumber() + 'M7' + '\n'

        # process the operation gcode
        gcode += parse(obj)

        # do the post_op
        if OUTPUT_COMMENTS:
            gcode += linenumber() + "(finish operation: %s)\n" % obj.Label
        for line in POST_OPERATION.splitlines(True):
            gcode += linenumber() + line

        # turn coolant off if required
        if not coolantMode == 'None':
            if OUTPUT_COMMENTS:
                gcode += linenumber() + '(Coolant Off:' + coolantMode + ')\n'
            gcode  += linenumber() +'M9' + '\n'

    # do the post_amble
    if OUTPUT_COMMENTS:
        gcode += "(begin postamble)\n"
    for line in POSTAMBLE.splitlines(True):
        gcode += linenumber() + line

    if FreeCAD.GuiUp and SHOW_EDITOR:
        dia = PostUtils.GCodeEditorDialog()
        dia.editor.setText(gcode)
        result = dia.exec_()
        if result:
            final = dia.editor.toPlainText()
        else:
            final = gcode
    else:
        final = gcode

    print("done postprocessing.")

    if not filename == '-':
        gfile = pythonopen(filename, "w")
        gfile.write(final)
        gfile.close()

    return final


def linenumber():
    # pylint: disable=global-statement
    global LINENR
    if OUTPUT_LINE_NUMBERS is True:
        LINENR += 5
        return "N" + str(LINENR) + " "
    return ""


def parse(pathobj):
    # pylint: disable=global-statement
    global PRECISION
    global MODAL
    global OUTPUT_DOUBLES
    global UNIT_FORMAT
    global UNIT_SPEED_FORMAT
    global RELATIVE_GCODE
    global LOCATION

    out = ""
    lastcommand = None
    precision_string = '.' + str(PRECISION) + 'f'

    currLocation = LOCATION if RELATIVE_GCODE else {}  # keep track for no doubles

    # the order of parameters
    # linuxcnc doesn't want K properties on XY plane  Arcs need work.
    params = ['X', 'Y', 'Z', 'A', 'B', 'C', 'I', 'J', 'F', 'S', 'T', 'Q', 'R', 'L', 'H', 'D', 'P']
    firstmove = Path.Command("G0", {"X": 0, "Y": 0, "Z": 0, "F": 0.0})
    currLocation.update(firstmove.Parameters)  # set First location Parameters

    if hasattr(pathobj, "Group"):  # We have a compound or project.
        # if OUTPUT_COMMENTS:
        #     out += linenumber() + "(compound: " + pathobj.Label + ")\n"
        for p in pathobj.Group:
            out += parse(p)
        return out
    else:  # parsing simple path

        # groups might contain non-path things like stock.
        if not hasattr(pathobj, "Path"):
            return out

        # if OUTPUT_COMMENTS:
        #     out += linenumber() + "(" + pathobj.Label + ")\n"

        for c in pathobj.Path.Commands:

            outstring = []
            command = c.Name
            outstring.append(command)

            # if modal: suppress the command if it is the same as the last one
            if MODAL is True:
                if command == lastcommand:
                    outstring.pop(0)

            if c.Name[0] == '(' and not OUTPUT_COMMENTS: # command is a comment
                continue

            # Now add the remaining parameters in order
            for param in params:
                if param in c.Parameters:
                    if param == 'F' and (currLocation[param] != c.Parameters[param] or OUTPUT_DOUBLES):
                        if c.Name not in ["G0", "G00"]:  # linuxcnc doesn't use rapid speeds
                            speed = Units.Quantity(c.Parameters['F'], FreeCAD.Units.Velocity)
                            if speed.getValueAs(UNIT_SPEED_FORMAT) > 0.0:
                                outstring.append(param + format(float(speed.getValueAs(UNIT_SPEED_FORMAT)), precision_string))
                        else:
                            continue
                    elif param == 'T':
                        outstring.append(param + str(int(c.Parameters['T'])))
                    elif param == 'H':
                        outstring.append(param + str(int(c.Parameters['H'])))
                    elif param == 'D':
                        outstring.append(param + str(int(c.Parameters['D'])))
                    elif param == 'S':
                        outstring.append(param + str(int(c.Parameters['S'])))
                    else:
                        if (not OUTPUT_DOUBLES) and (param in currLocation) and (currLocation[param] == c.Parameters[param]):
                            continue
                        else:
                            if RELATIVE_GCODE:
                                pos =  Units.Quantity(c.Parameters[param] - currLocation[param], FreeCAD.Units.Length)
                                print(f'currlocation: {currLocation[param]} param: {c.Parameters[param]} pos: {pos}')
                            else:
                                pos = Units.Quantity(c.Parameters[param], FreeCAD.Units.Length)


                            if pos >= 0:
                                sign = "+"
                            else:
                                sign = "-"
                                pos=abs(pos)

                            pval = math.modf(float(pos.getValueAs(UNIT_FORMAT)))
                            frac=str(int(pval[0]))[:3].ljust(3,"0")
                            intg=str(int(pval[1])).zfill(3)

                            stringout = f'{sign}{intg}{frac}'

                            #format(float(pos.getValueAs(UNIT_FORMAT)), precision_string)
                            print(stringout)
                            outstring.append(param + stringout)

            # store the latest command
            lastcommand = command
            currLocation.update(c.Parameters)

            # Check for Tool Change:
            if command == 'M6':
                # stop the spindle
                out += linenumber() + "M5\n"
                for line in TOOL_CHANGE.splitlines(True):
                    out += linenumber() + line

                # add height offset
                if USE_TLO:
                    tool_height = '\nG43 H' + str(int(c.Parameters['T']))
                    outstring.append(tool_height)

            if command == "message":
                if OUTPUT_COMMENTS is False:
                    out = []
                else:
                    outstring.pop(0)  # remove the command

            # prepend a line number and append a newline
            if len(outstring) >= 1:
                if OUTPUT_LINE_NUMBERS:
                    outstring.insert(0, (linenumber()))

                # append the line to the final output
                for w in outstring:
                    out += w + COMMAND_SPACE
                out = out.strip() + "\n"


        LOCATION = currLocation

        return out

print(__name__ + " gcode postprocessor loaded.")
relative_post.py (16,164 bytes)   

sliptonic

2020-04-22 23:15

manager   ~0014367

The attached post has two kinds of changes in it. The changes to make the relative gcode are, I think, broadly applicable and should be included in the linuxcnc reference post processor.

The changes to format the numbers in a specific way is unique to the Geg's EDM machine and should not be included.

Issue History

Date Modified Username Field Change
2020-04-21 14:38 sliptonic New Issue
2020-04-21 14:38 sliptonic Status new => assigned
2020-04-21 14:38 sliptonic Assigned To => sliptonic
2020-04-21 15:00 sliptonic FreeCAD Information <!--ATTENTION: COMPLETELY ERASE THIS AFTER PASTING YOUR Help > About FreeCAD > Copy to clipboard NOTE: just the snippet alone will do without anything else included. The ticket will not be submitted without it. --> =>
2020-04-22 22:48 sliptonic Note Added: 0014366
2020-04-22 22:48 sliptonic File Added: relative_post.py
2020-04-22 23:15 sliptonic Note Added: 0014367
2020-10-07 18:16 sliptonic Target Version => 0.20