Fix DXF issues on onshape export

README.md

Assorted tools needed when dealing with e.g. Onshape DXF exports.

Example usage to batch fix all .dxf files in a directory:

cd directory_with_dxf_files pip install ezdxf mkdir output for f in ls *.dxf; do python convert_onshape_dxf.py -i $f -o output/$f; done;

From https://github.com/ApproxEng/triangula/tree/master/tools

convert_onshape_dxf.py

__author__ = 'Tom Oinn'

import sys
import getopt
# Get ezdxf with 'pip install ezdxf', tested with Python2.7
import ezdxf


def mirror_coord(c):
    """
    If Z coordinate of c is less than zero, return mirrored around Y axis

    :param c:
        a coordinate (x,y,z)

    :returns:
        A flattened (Z set to 0) and optionally mirrored, copy of the input
    """
    (x, y, z) = c
    return (-x, y, 0)

def mirror(a):
    """
    Return angle mirrored around 180 degrees
    """
    a = 180 - a
    if a < 0:
        a += 360
    return a


def main(inputfile, outputfile):
    """
    Mirror all CIRCLE and ARC entities if their centre coordinates are negative in Z axis

    :param inputfile:
        Name of a DXF file to read
    :param outputfile:
        Name of a DXF file to write
    """
    dwg = ezdxf.readfile(inputfile)
    for e in dwg.entities:
        (x,y,z) = e.dxf.extrusion
        if z < 0:
            if e.dxftype() == 'CIRCLE':
                e.dxf.center = mirror_coord(e.dxf.center)
            elif e.dxftype() == 'ARC':
                start_angle = e.dxf.start_angle
                end_angle = e.dxf.end_angle
                e.dxf.start_angle = mirror(end_angle)
                e.dxf.end_angle = mirror(start_angle)
                e.dxf.center = mirror_coord(e.dxf.center)
        e.dxf.extrusion = (0,0,1.0)
    dwg.saveas(outputfile)


USAGE_MESSAGE = 'convert_onshape_dxf.py [-i|--ifile] <input_file> [-o|--ofile] <outputfile>'

if __name__ == '__main__':
    input_file = None
    output_file = None
    try:
        opts, args = getopt.getopt(sys.argv[1:], 'i:o:', ['ifile=', 'ofile='])
    except getopt.GetoptError:
        print USAGE_MESSAGE
        sys.exit(2)
    for opt, arg in opts:
        if opt in ("-i", "--ifile"):
            input_file = arg
        elif opt in ("-o", "--ofile"):
            output_file = arg
    if input_file is None or output_file is None:
        print(USAGE_MESSAGE)
        sys.exit(2)
    main(input_file, output_file)