| #!/usr/bin/env python3 |
| # License: Apache-2.0 |
| """ |
| This program converts a GDSII (2D) layout file to a single glTF (3D) file containing one baked mesh for each layer |
| |
| USAGE: |
| - edit the "layerstack" variable in the "CONFIGURATION" section below |
| - run "gdsiiobj file.gds" |
| OUTPUT: |
| - one file named: file.gds.gltf |
| |
| The program takes one argument, a path to a GDSII file. It reads shapes from |
| each layer of the GDSII file, converts them to polygon boundaries, then makes |
| a triangle mesh for each GDSII layer by extruding the polygons to given sizes. |
| |
| All units, including the units of the exported file, are the GDSII file's |
| user units (often microns). |
| |
| Original script by mbalestrini: https://github.com/mbalestrini/GDS2Obj , also Licensed Apache-2.0 |
| """ |
| |
| import sys # read command-line arguments |
| import gdspy # open gds file |
| import numpy as np # fast math on lots of points |
| import triangle # triangulate polygons |
| |
| import pygltflib |
| from pygltflib import BufferFormat |
| from pygltflib.validator import validate, summary |
| |
| # get the input file name |
| if len(sys.argv) < 2: # sys.argv[0] is the name of the program |
| print("Error: need exactly one file as a command line argument.") |
| sys.exit(0) |
| gdsii_file_path = sys.argv[1] |
| |
| ########## CONFIGURATION (EDIT THIS PART) ##################################### |
| |
| # choose which GDSII layers to use |
| |
| layerstack = { |
| (0,0): {'name':'substrate', 'zmin':-2, 'zmax':0, 'color':[ 0.2, 0.2, 0.2, 1.0]}, |
| (21,0): {'name':'Nwell', 'zmin':-0.5, 'zmax':0.01, 'color':[ 0.4, 0.4, 0.4, 1.0]}, |
| (22,0): {'name':'COMP (1)', 'zmin':-0.12, 'zmax':0.02, 'color':[ 0.9, 0.9, 0.9, 1.0]}, |
| (30,0): {'name':'Poly2', 'zmin':0, 'zmax':0.18, 'color':[ 0.75, 0.35, 0.46, 1.0]}, |
| (53,0): {'name':'MetalTop', 'zmin':0, 'zmax':0.936, 'color':[ 0.2, 0.2, 0.2, 1.0]}, |
| #(67,20): {'name':'li1', 'zmin':0.936, 'zmax':1.136, 'color':[ 1.0, 0.81, 0.55, 1.0]}, |
| (33,0): {'name':'Contact', 'zmin':1.011, 'zmax':1.376, 'color':[ 0.2, 0.2, 0.2, 1.0]}, |
| (34,0): {'name':'Metal1', 'zmin':1.376, 'zmax':1.736, 'color':[ 0.16, 0.38, 0.83, 1.0]}, |
| (35,0): {'name':'Via1', 'zmin':1.736,'zmax':2, 'color':[ 0.2, 0.2, 0.2, 1.0]}, |
| (36,0): {'name':'Metal2', 'zmin':2, 'zmax':2.36, 'color':[ 0.65, 0.75, 0.9, 1.0]}, |
| (38,0): {'name':'Via2', 'zmin':2.36, 'zmax':2.786, 'color':[ 0.2, 0.2, 0.2, 1.0]}, |
| (42,0): {'name':'Metal3', 'zmin':2.786, 'zmax':3.631, 'color':[ 0.2, 0.62, 0.86, 1.0]}, |
| (40,0): {'name':'Via3', 'zmin':3.631, 'zmax':4.0211, 'color':[ 0.2, 0.2, 0.2, 1.0]}, |
| (46,0): {'name':'Metal4', 'zmin':4.0211, 'zmax':4.8661, 'color':[ 0.15, 0.11, 0.38, 1.0]}, |
| (41,0): {'name':'Via4', 'zmin':4.8661, 'zmax':5.371, 'color':[ 0.2, 0.2, 0.2, 1.0]}, |
| (81,0): {'name':'Metal5', 'zmin':5.371, 'zmax':6.6311, 'color':[ 0.4, 0.4, 0.4, 1.0]}, |
| } |
| |
| #layerstack = { |
| # (235,4): {'name':'substrate', 'zmin':-2, 'zmax':0, 'color':[ 0.2, 0.2, 0.2, 1.0]}, |
| # (64,20): {'name':'nwell', 'zmin':-0.5, 'zmax':0.01, 'color':[ 0.4, 0.4, 0.4, 1.0]}, |
| # # (65,44): {'name':'tap', 'zmin':0, 'zmax':0.1, 'color':[ 0.4, 0.4, 0.4, 1.0]}, |
| # (65,20): {'name':'diff', 'zmin':-0.12, 'zmax':0.02, 'color':[ 0.9, 0.9, 0.9, 1.0]}, |
| # (66,20): {'name':'poly', 'zmin':0, 'zmax':0.18, 'color':[ 0.75, 0.35, 0.46, 1.0]}, |
| # (66,44): {'name':'licon', 'zmin':0, 'zmax':0.936, 'color':[ 0.2, 0.2, 0.2, 1.0]}, |
| # (67,20): {'name':'li1', 'zmin':0.936, 'zmax':1.136, 'color':[ 1.0, 0.81, 0.55, 1.0]}, |
| # (67,44): {'name':'mcon', 'zmin':1.011, 'zmax':1.376, 'color':[ 0.2, 0.2, 0.2, 1.0]}, |
| # (68,20): {'name':'met1', 'zmin':1.376, 'zmax':1.736, 'color':[ 0.16, 0.38, 0.83, 1.0]}, |
| # (68,44): {'name':'via', 'zmin':1.736,'zmax':2, 'color':[ 0.2, 0.2, 0.2, 1.0]}, |
| # (69,20): {'name':'met2', 'zmin':2, 'zmax':2.36, 'color':[ 0.65, 0.75, 0.9, 1.0]}, |
| # (69,44): {'name':'via2', 'zmin':2.36, 'zmax':2.786, 'color':[ 0.2, 0.2, 0.2, 1.0]}, |
| # (70,20): {'name':'met3', 'zmin':2.786, 'zmax':3.631, 'color':[ 0.2, 0.62, 0.86, 1.0]}, |
| # (70,44): {'name':'via3', 'zmin':3.631, 'zmax':4.0211, 'color':[ 0.2, 0.2, 0.2, 1.0]}, |
| # (71,20): {'name':'met4', 'zmin':4.0211, 'zmax':4.8661, 'color':[ 0.15, 0.11, 0.38, 1.0]}, |
| # (71,44): {'name':'via4', 'zmin':4.8661, 'zmax':5.371, 'color':[ 0.2, 0.2, 0.2, 1.0]}, |
| # (72,20): {'name':'met5', 'zmin':5.371, 'zmax':6.6311, 'color':[ 0.4, 0.4, 0.4, 1.0]}, |
| # # (83,44): { 'zmin':0, 'zmax':0.1, 'name':'text'}, |
| #} |
| |
| |
| binaryBlob = bytes() |
| gltf = pygltflib.GLTF2() |
| scene = pygltflib.Scene() |
| gltf.scenes.append(scene) |
| buffer = pygltflib.Buffer() |
| gltf.buffers.append(buffer) |
| |
| for layer in layerstack: |
| mainMaterial = pygltflib.Material() |
| mainMaterial.doubleSided = False |
| mainMaterial.name = layerstack[layer]['name'] |
| mainMaterial.pbrMetallicRoughness = { |
| "baseColorFactor": layerstack[layer]['color'], |
| "metallicFactor": 0.5, |
| "roughnessFactor": 0.5 |
| } |
| gltf.materials.append(mainMaterial) |
| |
| root_node = pygltflib.Node() |
| root_node.name = 'main' |
| gltf.nodes.append(root_node) |
| |
| tris_count = 0 |
| |
| ########## INPUT ############################################################## |
| |
| # First, the input file is read using the gdspy library, which interprets the |
| # GDSII file and formats the data Python-style. |
| # See https://gdspy.readthedocs.io/en/stable/index.html for documentation. |
| # Second, the boundaries of each shape (polygon or path) are extracted for |
| # further processing. |
| |
| print('Reading GDSII file {}...'.format(gdsii_file_path)) |
| gdsii = gdspy.GdsLibrary() |
| gdsii.read_gds(gdsii_file_path, units='import') |
| |
| print('Extracting polygons...') |
| |
| for cell in gdsii.cells.values(): |
| if 'fill' in cell.name or 'antenna' in cell.name or 'endcap' in cell.name: |
| cell.polygons.clear() |
| |
| |
| for cell in gdsii.top_level(): # loop through cells to read paths and polygons |
| layers = {} # array to hold all geometry, sorted into layers |
| |
| print ("\nProcessing cell: ", cell.name) |
| |
| print("Flatenning") |
| |
| cell.flatten() |
| |
| # $$$CONTEXT_INFO$$$ is a separate, non-standard compliant cell added |
| # optionally by KLayout to store extra information not needed here. |
| # see https://www.klayout.de/forum/discussion/1026/very- |
| # important-gds-exported-from-k-layout-not-working-on-cadence-at-foundry |
| if cell.name == '$$$CONTEXT_INFO$$$': |
| continue # skip this cell |
| |
| print ("\tpaths loop. total paths:" , len(cell.paths)) |
| # loop through paths in cell |
| for path in cell.paths: |
| lnum = (path.layers[0],path.datatypes[0]) # GDSII layer number |
| |
| if not lnum in layerstack.keys(): |
| continue |
| |
| layers[lnum] = [] if not lnum in layers else layers[lnum] |
| # add paths (converted to polygons) that layer |
| for poly in path.get_polygons(): |
| layers[lnum].append((poly, None, False)) |
| |
| print ("\tpolygons loop. total polygons:" , len(cell.polygons)) |
| # loop through polygons (and boxes) in cell |
| for polygon in cell.polygons: |
| lnum = (polygon.layers[0],polygon.datatypes[0]) # same as before... |
| |
| if not lnum in layerstack.keys(): |
| continue |
| |
| layers[lnum] = [] if not lnum in layers else layers[lnum] |
| for poly in polygon.polygons: |
| layers[lnum].append((poly, None, False)) |
| |
| |
| |
| |
| """ |
| At this point, "layers" is a Python dictionary structured as follows: |
| |
| layers = { |
| 0 : [ ([[x1, y1], [x2, y2], ...], None, False), ... ] |
| 1 : [ ... ] |
| 2 : [ ... ] |
| ... |
| } |
| |
| Each dictionary key is a GDSII layer number (0-255), and the value of the |
| dictionary at that key (if it exists; keys were only created for layers with |
| geometry) is a list of polygons in that GDSII layer. Each polygon is a 3-tuple |
| whose first element is a list of points (2-element lists with x and y |
| coordinates), second element is None (for the moment; this will be used later), |
| and third element is False (whether the polygon is clockwise; will be updated). |
| """ |
| |
| ########## TRIANGULATION ###################################################### |
| |
| # An STL file is a list of triangles, so the polygons need to be filled with |
| # triangles. This is a surprisingly hard algorithmic problem, especially since |
| # there are few limits on what shapes GDSII file polygons can be. So we use the |
| # Python triangle library (documentation is at https://rufat.be/triangle/), |
| # which is a Python interface to a fast and well-written C library also called |
| # triangle (with documentation at https://www.cs.cmu.edu/~quake/triangle.html). |
| |
| print('\tTriangulating polygons...') |
| |
| |
| num_triangles = {} # will store the number of triangles for each layer |
| |
| # loop through all layers |
| for layer_number, polygons in layers.items(): |
| |
| # but skip layer if it won't be exported |
| if not layer_number in layerstack.keys(): |
| continue |
| |
| num_triangles[layer_number] = 0 |
| |
| # loop through polygons in layer |
| for index, (polygon, _, _) in enumerate(polygons): |
| |
| num_polygon_points = len(polygon) |
| |
| # determine whether polygon points are CW or CCW |
| area = 0 |
| for i, v1 in enumerate(polygon): # loop through vertices |
| v2 = polygon[(i+1) % num_polygon_points] |
| area += (v2[0]-v1[0])*(v2[1]+v1[1]) # integrate area |
| |
| clockwise = area > 0 |
| |
| # GDSII implements holes in polygons by making the polygon edge |
| # wrap into the hole and back out along the same line. However, |
| # this confuses the triangulation library, which fills the holes |
| # with extra triangles. Avoid this by moving each edge back a |
| # very small amount so that no two edges of the same polygon overlap. |
| delta = 0.00001 # inset each vertex by this much (smaller has broken one file) |
| points_i = polygon # get list of points |
| points_j = np.roll(points_i, -1, axis=0) # shift by 1 |
| points_k = np.roll(points_i, 1, axis=0) # shift by -1 |
| # calculate normals for each edge of each vertex (in parallel, for speed) |
| normal_ij = np.stack((points_j[:, 1]-points_i[:, 1], |
| points_i[:, 0]-points_j[:, 0]), axis=1) |
| normal_ik = np.stack((points_i[:, 1]-points_k[:, 1], |
| points_k[:, 0]-points_i[:, 0]), axis=1) |
| length_ij = np.linalg.norm(normal_ij, axis=1) |
| length_ik = np.linalg.norm(normal_ik, axis=1) |
| normal_ij /= np.stack((length_ij, length_ij), axis=1) |
| normal_ik /= np.stack((length_ik, length_ik), axis=1) |
| if clockwise: |
| normal_ij = -1*normal_ij |
| normal_ik = -1*normal_ik |
| # move each vertex inward along its two edge normals |
| polygon = points_i - delta*normal_ij - delta*normal_ik |
| |
| # In an extreme case of the above, the polygon edge doubles back on |
| # itself on the same line, resulting in a zero-width segment. I've |
| # seen this happen, e.g., with a capital "N"-shaped hole, where |
| # the hole split line cuts out the "N" shape but splits apart to |
| # form the triangle cutout in one side of the shape. In any case, |
| # simply moving the polygon edges isn't enough to deal with this; |
| # we'll additionally mark points just outside of each edge, between |
| # the original edge and the delta-shifted edge, as outside the polygon. |
| # These parts will be removed from the triangulation, and this solves |
| # just this case with no adverse affects elsewhere. |
| hole_delta = 0.00001 # small fraction of delta |
| holes = 0.5*(points_j+points_i) - hole_delta*delta*normal_ij |
| # HOWEVER: sometimes this causes a segmentation fault in the triangle |
| # library. I've observed this as a result of certain various polygons. |
| # Frustratingly, the fault can be bypassed by *rotating the polygons* |
| # by like 30 degrees (exact angle seems to depend on delta values) or |
| # moving one specific edge outward a bit. I have absolutely no idea |
| # what is wrong. In the interest of stability over full functionality, |
| # this is disabled. TODO: figure out why this happens and fix it. |
| use_holes = False |
| |
| # triangulate: compute triangles to fill polygon |
| point_array = np.arange(num_polygon_points) |
| edges = np.transpose(np.stack((point_array, np.roll(point_array, 1)))) |
| if use_holes: |
| triangles = triangle.triangulate(dict(vertices=polygon, |
| segments=edges, |
| holes=holes), opts='p') |
| else: |
| triangles = triangle.triangulate(dict(vertices=polygon, |
| segments=edges), opts='p') |
| |
| if not 'triangles' in triangles.keys(): |
| triangles['triangles'] = [] |
| |
| # each line segment will make two triangles (for a rectangle), and the polygon |
| # triangulation will be copied on the top and bottom of the layer. |
| num_triangles[layer_number] += num_polygon_points*2 + \ |
| len(triangles['triangles'])*2 |
| polygons[index] = (polygon, triangles, clockwise) |
| |
| |
| |
| zmin = layerstack[layer_number]['zmin'] |
| zmax = layerstack[layer_number]['zmax'] |
| layername = layerstack[layer_number]['name'] |
| |
| print("\nProcesing layer " + layername + "\nExtruding polygons and preparing vertices and faces") |
| positions = [] |
| indices = [] |
| indices_offset = 0 |
| for i,(_, poly_data, clockwise) in enumerate(polygons): |
| |
| |
| p_positions_top = np.insert(poly_data['vertices'], 2, zmax, axis=1) |
| p_positions_bottom = np.insert( poly_data['vertices'] , 2, zmin, axis=1) |
| |
| p_positions = np.concatenate( (p_positions_top, p_positions_bottom) ) |
| p_indices_top = poly_data['triangles'] |
| p_indices_bottom = np.flip ((p_indices_top+len(p_positions_top)), axis=1 ) |
| |
| ind_list_top = np.arange(len(p_positions_top)) |
| ind_list_bottom = np.arange(len(p_positions_top)) + len(p_positions_top) |
| |
| if(clockwise): |
| ind_list_top = np.flip(ind_list_top, axis=0) |
| ind_list_bottom = np.flip(ind_list_bottom, axis=0) |
| |
| p_indices_right = np.stack( (ind_list_bottom, np.roll(ind_list_bottom, -1, axis=0) , np.roll(ind_list_top, -1, axis=0)), axis=1 ) |
| p_indices_left = np.stack( ( np.roll(ind_list_top, -1, axis=0), ind_list_top , ind_list_bottom ) , axis=1) |
| |
| p_indices = np.concatenate( (p_indices_top, p_indices_bottom, p_indices_right, p_indices_left) ) |
| |
| if(len(positions)==0): |
| positions = p_positions |
| else: |
| positions = np.append(positions , p_positions, axis=0) |
| if(len(indices)==0): |
| indices = p_indices |
| else: |
| indices = np.append(indices, p_indices + indices_offset, axis=0) |
| indices_offset += len(p_positions) |
| |
| |
| indices_binary_blob = indices.astype(np.uint32).flatten().tobytes() |
| positions_binary_blob = positions.astype(np.float32).tobytes() |
| |
| bufferView1 = pygltflib.BufferView() |
| bufferView1.buffer = 0 |
| bufferView1.byteOffset = len(binaryBlob) |
| bufferView1.byteLength = len(indices_binary_blob) |
| bufferView1.target = pygltflib.ELEMENT_ARRAY_BUFFER |
| gltf.bufferViews.append(bufferView1) |
| |
| accessor1 = pygltflib.Accessor() |
| accessor1.bufferView = len(gltf.bufferViews)-1 |
| accessor1.byteOffset = 0 |
| accessor1.componentType = pygltflib.UNSIGNED_INT |
| accessor1.type = pygltflib.SCALAR |
| accessor1.count = indices.size |
| accessor1.max = [int(indices.max())] |
| accessor1.min = [int(indices.min())] |
| gltf.accessors.append(accessor1) |
| |
| binaryBlob = binaryBlob + indices_binary_blob |
| |
| bufferView2 = pygltflib.BufferView() |
| bufferView2.buffer = 0 |
| bufferView2.byteOffset = len(binaryBlob) |
| bufferView2.byteLength = len(positions_binary_blob) |
| bufferView2.target = pygltflib.ARRAY_BUFFER |
| gltf.bufferViews.append(bufferView2) |
| |
| positions_count = len(positions) |
| accessor2 = pygltflib.Accessor() |
| accessor2.bufferView = len(gltf.bufferViews)-1 |
| accessor2.byteOffset = 0 |
| accessor2.componentType = pygltflib.FLOAT |
| accessor2.count = positions_count |
| accessor2.type = pygltflib.VEC3 |
| accessor2.max = positions.max(axis=0).tolist() |
| accessor2.min = positions.min(axis=0).tolist() |
| gltf.accessors.append(accessor2) |
| |
| binaryBlob = binaryBlob + positions_binary_blob |
| |
| mesh = pygltflib.Mesh() |
| mesh_primitive = pygltflib.Primitive() |
| mesh_primitive.indices = len(gltf.accessors)-2 |
| mesh_primitive.attributes.POSITION = len(gltf.accessors)-1 |
| |
| mesh_primitive.material = list(layerstack).index(layer_number) |
| |
| mesh.primitives.append(mesh_primitive) |
| |
| gltf.meshes.append(mesh) |
| |
| layer_node = pygltflib.Node() |
| layer_node.name = layername |
| layer_node.mesh = len(gltf.meshes)-1 |
| gltf.nodes.append(layer_node) |
| root_node.children.append(len(gltf.nodes)-1) |
| tris_count += len(indices) |
| print(f'{len(indices)} tris') |
| |
| print("Saving gltf...") |
| filename = gdsii_file_path + ".gltf" |
| |
| gltf.set_binary_blob(binaryBlob) |
| buffer.byteLength = len(binaryBlob) |
| gltf.convert_buffers(BufferFormat.DATAURI) |
| |
| scene.nodes.append(0) |
| gltf.scene = 0 |
| |
| gltf.save(filename) |
| |
| |
| print('Done.') |
| print(f'{tris_count} total tris') |
