PyMOAB Script for compiling a non-overlapping set of STLs into a DAGMC model

stls_to_dagmc.py

#!/usr/bin/env python
# coding: utf-8

import glob
import json
import numpy as np

from pymoab import core, types

# skip graveyard volume for better viz
skip_graveyard = False

# create pymoab instance
mb = core.Core()

tags = dict()

SENSE_TAG_NAME = "GEOM_SENSE_2"
SENSE_TAG_SIZE = 2
tags['surf_sense'] = mb.tag_get_handle(SENSE_TAG_NAME, SENSE_TAG_SIZE, types.MB_TYPE_HANDLE, types.MB_TAG_SPARSE, create_if_missing=True)

tags['category'] = mb.tag_get_handle(types.CATEGORY_TAG_NAME, types.CATEGORY_TAG_SIZE, types.MB_TYPE_OPAQUE, types.MB_TAG_SPARSE, create_if_missing=True)
tags['name'] = mb.tag_get_handle(types.NAME_TAG_NAME, types.NAME_TAG_SIZE, types.MB_TYPE_OPAQUE, types.MB_TAG_SPARSE, create_if_missing=True)
tags['geom_dimension'] = mb.tag_get_handle(types.GEOM_DIMENSION_TAG_NAME, 1, types.MB_TYPE_INTEGER, types.MB_TAG_DENSE, create_if_missing=True)

# Global ID is a default tag, just need the name to retrieve
tags['global_id']= mb.tag_get_handle(types.GLOBAL_ID_TAG_NAME)

surface_id = 1
volume_id = 1

# handle metadata
with open("manifest.json") as fh:
    manifest = json.load(fh)

material_dict = dict()

for item in manifest:

    stl_filename = item['stl_filename']

    if skip_graveyard and "graveyard" in stl_filename.lower():
        continue

    surface_set = mb.create_meshset()
    volume_set = mb.create_meshset()

    # recent versions of MOAB handle this automatically
    # but best to go ahead and do it manually
    mb.tag_set_data(tags['global_id'], volume_set, volume_id)
    volume_id += 1
    mb.tag_set_data(tags['global_id'], surface_set, surface_id)
    surface_id += 1

    # set geom IDs
    mb.tag_set_data(tags['geom_dimension'], volume_set, 3)
    mb.tag_set_data(tags['geom_dimension'], surface_set, 2)

    # set category tag values
    mb.tag_set_data(tags['category'], volume_set, "Volume")
    mb.tag_set_data(tags['category'], surface_set, "Surface")

    # establish parent-child relationship
    mb.add_parent_child(volume_set, surface_set)

    # set surface sense
    sense_data = [volume_set, np.uint64(0)]
    mb.tag_set_data(tags['surf_sense'], surface_set, sense_data)

    # load the stl triangles/vertices into the surface set
    mb.load_file(stl_filename, surface_set)

    material_name = item['material']

    if skip_graveyard and "graveyard" in stl_filename.lower():
        continue

    group_set = mb.create_meshset()
    mb.tag_set_data(tags['category'], group_set, "Group")
    print("mat:{}".format(material_name))
    mb.tag_set_data(tags['name'], group_set, "mat:{}".format(material_name))
    mb.tag_set_data(tags['geom_dimension'], group_set, 4)

    # add the volume to this group set
    mb.add_entity(group_set, volume_set)

all_sets = mb.get_entities_by_handle(0)

file_set = mb.create_meshset()

mb.add_entities(file_set, all_sets)

mb.write_file("dagmc.h5m")
mb.write_file("dagmc.vtk")