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Postprocessing script to make FreeCAD paths importible by Easel (WIP)
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# *************************************************************************** | |
# * (c) Benno Evers (bennoe@apache.org) 2019 * | |
# * * | |
# * 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 | |
TOOLTIP=''' | |
This is a post-processor for the Easel WebUI which can control various | |
models of CNC mills, i.e. Carvey, X-Carve and ShapeOko 1/2. | |
Note that it has only been tested with the Carvey. | |
Its main task is to linearize any arcs, since Easel only | |
supports linear movements. | |
''' | |
import datetime | |
import FreeCAD | |
import Part | |
import PathScripts.PostUtils as PostUtils | |
def export(objectslist, filename, argstring): | |
"Called when freecad exports a list of objects" | |
# TODO(bevers): Support multiple paths by concatenating them together. | |
if len(objectslist) > 1: | |
print("This script is unable to write more than one Path object") | |
return | |
obj = objectslist[0] | |
if not hasattr(obj, "Path"): | |
print("the given object is not a path") | |
return | |
gcode = postprocess(obj.Path.Commands) | |
# Debugging info | |
dia = PostUtils.GCodeEditorDialog() | |
dia.editor.setText(gcode) | |
result = dia.exec_() | |
gfile = open(filename, "w") | |
gfile.write(gcode) | |
gfile.close() | |
return result | |
def linearize_arc(start, end, center, normal, clockwise): | |
result = "; {} arc from {} to {}\n; around center point {}\n".format( | |
"Clockwise" if clockwise else "Counter-clockwise", | |
start, | |
end, | |
center) | |
radius = (center - start).Length | |
# Center everything at the origin for the following steps | |
start0 = start - center | |
end0 = end - center | |
EPSILON = 1e-7 | |
if (start0 + end0).Length < EPSILON: | |
# 180 degree angle | |
mid0 = normal.cross(start0) | |
elif (start0 - end0).Length < EPSILON: | |
# 360 degree angle | |
mid0 = -start0 | |
else: | |
# "Normal" angle | |
mid0 = radius*(start0 + end0).normalize() | |
# Check if mid-point is clockwise or counter-clockwise from the start. | |
mid_clockwise = normal.dot(start0.cross(mid0)) | |
# If it doesn't match the requested direction, choose the point on | |
# the other side of the circle. | |
if clockwise != mid_clockwise: | |
mid0 = -mid0 | |
mid = center + mid0 | |
arc = Part.ArcOfCircle(start, mid, end) | |
steps = 64 # TODO: make number of steps configurable | |
points = arc.discretize(steps) | |
c = [] | |
for p in points: | |
c.append("G1 X{} Y{} Z{}\n".format(p.x, p.y, p.z)) | |
return result + "".join(c) + "\n" | |
def postprocess(commands): | |
output = "; Generated by FreeCAD Easel post-processor.\n" | |
output += "G21 ; Metric units\n" # FreeCAD internal values are always metric. | |
# Currently supported internal commands: | |
# G0, G1, G2, G3 (Movement) | |
# G17, G18, G19 (Plane selection for G2/G3 arcs) | |
# G81, G82, G83 (Drilling) | |
# G90, G91 (Absolute/relative coordinates) | |
# Carvey starts at (20mm, 20mm, 20mm) after smart-clamp calibration. | |
# TODO: Check if this is different for the other easel-supported machines. | |
# TODO: Turn `state` into a FreeCAD.Vector ? | |
state = {'X': 20., 'Y': 20., 'Z': 20.} | |
normal = FreeCAD.Vector(0, 0, 1) | |
for cmd in commands: | |
if cmd.Name[0] == "(": | |
output += "; " + cmd.Name + "\n" | |
elif cmd.Name == "G0" or cmd.Name == "G1": | |
argnames = cmd.Parameters.keys() | |
if 'A' in argnames or 'B' in argnames or 'C' in argnames: | |
raise RuntimeError("A,B,C rotational axes currently not supported.") | |
if 'X' in argnames: | |
state['X'] = float(cmd.Parameters['X']) | |
if 'Y' in argnames: | |
state['Y'] = float(cmd.Parameters['Y']) | |
if 'Z' in argnames: | |
state['Z'] = float(cmd.Parameters['Z']) | |
# We could make generated file sizes slightly smaller by omitting | |
# unchanged coordinates, but so far we haven't hit a size limit in | |
# Easel. | |
output += "{} X{} Y{} Z{}\n".format(cmd.Name, state['X'], state['Y'], state['Z']) | |
elif cmd.Name == "G2" or cmd.Name == "G3": | |
# We are guaranteed that the arc described by these commands always | |
# lies in one of the three coordinate planes, and that the correct | |
# plane has already been set through the G17/G18/G19 commands. | |
# For arcs that are not aligned to a plane, FreeCAD will linearize | |
# them internally and generate a sequence of G1 movements itself. | |
argnames = cmd.Parameters.keys() | |
if 'A' in argnames or 'B' in argnames or 'C' in argnames: | |
raise RuntimeError("A,B,C rotational axes currently not supported.") | |
# Update final position | |
start = FreeCAD.Vector(state['X'], state['Y'], state['Z']) | |
end = FreeCAD.Vector(state['X'], state['Y'], state['Z']) | |
center = FreeCAD.Vector(state['X'], state['Y'], state['Z']) | |
if 'X' in argnames: | |
end.x = float(cmd.Parameters['X']) | |
if 'Y' in argnames: | |
end.y = float(cmd.Parameters['Y']) | |
if 'Z' in argnames: | |
end.z = float(cmd.Parameters['Z']) | |
if 'I' in argnames: | |
center.x += float(cmd.Parameters['I']) | |
if 'J' in argnames: | |
center.y += float(cmd.Parameters['J']) | |
if 'K' in argnames: | |
center.z += float(cmd.Parameters['K']) | |
clockwise = cmd.Name == "G2" | |
output += linearize_arc(start, end, center, normal, clockwise) | |
state = end_position | |
elif cmd.Name == "G81" or cmd.Name == "G82" or cmd.Name == "G83": | |
raise RuntimeError("Drilling commands (G8x) currently not supported.") | |
elif cmd.Name == "G90": | |
output += "G90 ; Absolute coordinate mode\n" | |
elif cmd.Name == "G91": | |
raise RuntimeError("Relative coordinate mode (G91) currently not supported.") | |
elif cmd.Name == "G17": # Use the xy-plane for arc movements. | |
normal = FreeCAD.Vector(0, 0, 1) | |
elif cmd.Name == "G18": # Use the zx-plane for arc movements. | |
normal = FreeCAD.Vector(0, 1, 0) | |
elif cmd.Name == "G19": # Use the yz-plane for arc movements. | |
normal = FreeCAD.Vector(1, 0, 0) | |
else: | |
# TODO: Maybe just output unknown commands unchanged? | |
raise RuntimeError("Unexpected internal G-Code command {}".format(cmd.Name)) | |
return output | |
print(__name__ + " gcode postprocessor loaded.") |
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