read_IGES.py

#!/usr/bin/env python
import os
from iges.curves_surfaces import *  # never, ever do this
from iges.entity import *   # or this

# http://ts.nist.gov/Standards/IGES/specfigures/index.cfm

# Setup
fileName = 'revB_alveolus_v5a_export.igs'
#fileName = 'F126x.igs'

# Load
f = open(fileName, 'r')

param_string = ''
params = []
entity_list = []
entity_index = 0
displayed = False
first_dict_line = True
first_global_line = True
first_param_line = True
global_string = ""
pointer_dict = {}

for line in f.readlines():
    data = line[:80]
    id_code = line[72]

    if id_code == 'S':     # Start
        pass
#        print(data)

    elif id_code == 'G':   # Global
        global_string += data   # Consolidate all global lines
        if first_global_line:
            param_sep = data[2]
            record_sep = data[6]
            first_global_line = False

        # Record separator denotes end of global section
        if global_string.strip()[-1] == record_sep:
            process_global_section(global_string)

    elif id_code == 'D':   # Directory entry
        if first_dict_line:
            entity_type_number = int(data[0:8].strip())
            # Curve and surface entities.  See IGES spec v5.3, p. 38, Table 3
            if entity_type_number == 100:   # Circular arc
                e = Entity()
            elif entity_type_number == 102: # Composite curve
                e = Entity()
            elif entity_type_number == 104: # Conic arc
                e = Entity()
            elif entity_type_number == 108: # Plane
                e = Entity()
            elif entity_type_number == 110: # Line
                e = Line()
            elif entity_type_number == 112: # Parametric spline curve
                e = Entity()
            elif entity_type_number == 114: # Parametric spline surface
                e = Entity()
            elif entity_type_number == 116: # Point
                e = Entity()
            elif entity_type_number == 118: # Ruled surface
                e = Entity()
            elif entity_type_number == 120: # Surface of revolution
                e = Entity()
            elif entity_type_number == 122: # Tabulated cylinder
                e = Entity()
            elif entity_type_number == 124: # Transformation matrix
                e = Entity()
            elif entity_type_number == 126: # Rational B-spline curve
                e = RationalBSplineCurve()
            elif entity_type_number == 128: # Rational B-spline surface
                e = Entity()
            # Need to add more ...
            
            # CSG Entities. See IGES spec v5.3, p. 42, Section 3.3
            elif entity_type_number == 150: # Block
                e = Entity()

            # B-Rep entities.  See IGES spec v5.3, p. 43, Section 3.4
            elif  entity_type_number == 186:
                e = Entity()

            # Annotation entities.  See IGES spec v5.3, p. 46, Section 3.5
            elif  entity_type_number == 202:
                e = Entity()

            # Structural entities.  See IGES spec v5.3, p. 50, Section 3.6
            elif  entity_type_number == 132:
                e = Entity()

            else:
                e = Entity()

            e.add_section(data[0:8], 'entity_type_number')
            e.add_section(data[8:16], 'parameter_pointer')
            e.add_section(data[16:24], 'structure')
            e.add_section(data[24:32], 'line_font_pattern')
            e.add_section(data[32:40], 'level')
            e.add_section(data[40:48], 'view')
            e.add_section(data[48:56], 'transform')
            e.add_section(data[56:65], 'label_assoc')
            e.add_section(data[65:72], 'status_number')
            e.sequence_number = int(data[73:].strip())

            first_dict_line = False
        else:
            e.add_section(data[8:16], 'line_weight_number')
            e.add_section(data[16:24], 'color_number')
            e.add_section(data[24:32], 'param_line_count')
            e.add_section(data[32:40], 'form_number')
            e.add_section(data[56:64], 'entity_label', type='string')
            e.add_section(data[64:72], 'entity_subs_num')

            first_dict_line = True
            entity_list.append(e)
            pointer_dict.update({e.sequence_number : entity_index})
            entity_index += 1

    elif id_code == 'P':   # Parameter data
        # Concatenate multiple lines into one string
        if first_param_line:
            param_string = data[:64]
            directory_pointer = int(data[64:72].strip())
            first_param_line = False
        else:
            param_string += data[:64]

        if param_string.strip()[-1] == record_sep:
            first_param_line = True
            param_string = param_string.strip()[:-1]
            parameters = param_string.split(param_sep)
            entity_list[pointer_dict[directory_pointer]].add_parameters(parameters)

    elif id_code == 'T':   # Terminate
        pass
f.close()

for entity in entity_list:
    if entity.d['entity_type_number'] == 126:
        print entity