Support binary .cli (Common Layer Interface) Build FIles via libslm

[drlukeparry]

This file format was a consortium agreed standard that provided a efficient format for scan vector information originally designed for SLA systems. This file format is recognised as the precursor to the native proprietary EOS .sli file format.

The specification has been documented on the following page:

https://www.hmilch.net/downloads/cli_format.html

The file format has limited uses now on most machines, but is a useful agnostic and open file format for those wishing to explore and learn about the structure and generation of machine build files typically used in AM process featuring 1D point source sources.

Thanks to Lu for the .cli file format example below:

cube-10mm_000_s1_vs.cli.zip

Following code excerpt reads the .cli file format

import re
import os
import struct
import numpy as np

import pyslm
import pyslm.geometry
import pyslm.visualise

def read_uint32(file, count=1):
    return np.fromfile(file, count=count, dtype=np.uint32)

def read_int32(file, count=1):
    return np.fromfile(file, count=count, dtype=np.int32)

def read_int16(file, count=1):
    return np.fromfile(file, count=count, dtype=np.int16)

def read_uint16(file, count=1):
    return np.fromfile(file, count=count, dtype=np.uint16)

def read_uint8(file, count=1):
    return np.fromfile(file, count=count, dtype=np.uint8)

def read_floats(file, count=1):
    return np.fromfile(file, count=count, dtype=np.float32)

# Read the layer
LONG_HATCH_SECTION = 132
SHORT_HATCH_SECTION = 131
LONG_POLYLINE_SECTION = 130
SHORT_POLYLINE_SECTION = 129
SHORT_LAYER_SECTION = 128
LONG_LAYER_SECTION = 127

filename ="cube-10mm_000_s1_vs.cli"

file = open(filename, "rb")

"""
Read the .cli header
"""

header = file.readline().decode("ascii").rstrip("\n")

if header != "$$HEADERSTART":
    raise ValueError("Not .cls file")

fileType  = file.readline().decode("ascii").rstrip("\n")

if fileType != "$$BINARY":
    raise ValueError("not binary file")

line = file.read(11)
params = {}
while line != "$$HEADEREND":

    file.seek(-11, 1)

    # Read the textual line in the header
    line = file.readline()

    if not line:
        break

    line = line.decode("latin-1").rstrip("\n")

    m = re.search("^\${2}(.*)/(.*)", line)

    params[m.group(1)] = m.group(2)

    line = file.read(11).decode("ascii")

id = read_uint16(file)

layers = []

params['UNITS'] = float(params['UNITS'])

while id == SHORT_LAYER_SECTION or id == LONG_LAYER_SECTION:

    layer = pyslm.geometry.Layer()
    layer.z = 0

    if id == LONG_LAYER_SECTION:
        layer.z = read_floats(file,1)
    elif id == SHORT_LAYER_SECTION:
        layer.z = read_uint16(file)

    id  = read_uint16(file)

    while id == SHORT_POLYLINE_SECTION or id == LONG_POLYLINE_SECTION or id == SHORT_HATCH_SECTION or id == LONG_HATCH_SECTION:
        geom = None
        if id == SHORT_POLYLINE_SECTION:
            geom = pyslm.geometry.ContourGeometry()
            geom.bid = read_uint8(file)
            geom.dir = read_uint16(file)
            numPoints = read_uint16(file)

            geom.coods = read_int16(file, 2*int(numPoints)).astype(np.float32).reshape(-1,2) * params['UNITS']

        elif id == LONG_POLYLINE_SECTION:
            geom = pyslm.geometry.ContourGeometry()

            geom.bid = read_uint32(file)
            geom.dir = read_uint32(file)
            numPoints = read_uint32(file)
            geom.coords = read_floats(file, 2 * int(numPoints)).reshape(-1,2)

        elif id == SHORT_HATCH_SECTION:
            geom = pyslm.geometry.HatchGeometry()
            geom.bid = read_uint16(file)
            numPoints = read_uint16(file)

            geom.coords = read_int16(file, 4 * int(numPoints)).astype(np.float32).reshape(-1,2) * params['UNITS']

        elif id == LONG_HATCH_SECTION:
            geom = pyslm.geometry.HatchGeometry()
            geom.bid = read_uint32(file)
            numPoints = read_uint32(file)

            geom.coords = read_floats(file, 4 * int(numPoints)).reshape(-1,2)

        layer.geometry.append(geom)
        id = read_uint16(file)

    print('id', id)
    layers.append(layer)

print('Total Path Distance: {:.1f} mm'.format(pyslm.analysis.getLayerPathLength(layers[0])))

pyslm.visualise.plot(layers[1], plot3D=False, plotOrderLine=True, plotArrows=False)

`