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# SPDX-License-Identifier: GPL-2.0-or-later
# Copyright 2010-2021 Adam Dominec <adominec@gmail.com>
## Code structure
# This file consists of several components, in this order:
# * Unfolding and baking
# * Export (SVG or PDF)
# * User interface
# During the unfold process, the mesh is mirrored into a 2D structure: UVFace, UVEdge, UVVertex.
bl_info = {
"name": "Export Paper Model",
"author": "Addam Dominec",
"location": "File > Export > Paper Model",
"warning": "",
"description": "Export printable net of the active mesh",
"doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/paper_model.html",
"category": "Import-Export",
}
# Task: split into four files (SVG and PDF separately)
# * does any portion of baking belong into the export module?
# * sketch out the code for GCODE and two-sided export
# QuickSweepline is very much broken -- it throws GeometryError for all nets > ~15 faces
# rotate islands to minimize area -- and change that only if necessary to fill the page size
# check conflicts in island naming and either:
# * append a number to the conflicting names or
# * enumerate faces uniquely within all islands of the same name (requires a check that both label and abbr. equals)
import bpy
import bl_operators
import mathutils as M
from re import compile as re_compile
from itertools import chain, repeat, product, combinations
from math import pi, ceil, asin, atan2
import os.path as os_path
default_priority_effect = {
'CONVEX': 0.5,
'CONCAVE': 1,
'LENGTH': -0.05
}
global_paper_sizes = [
('USER', "User defined", "User defined paper size"),
('A4', "A4", "International standard paper size"),
('A3', "A3", "International standard paper size"),
('US_LETTER', "Letter", "North American paper size"),
('US_LEGAL', "Legal", "North American paper size")
]
def first_letters(text):
"""Iterator over the first letter of each word"""
for match in first_letters.pattern.finditer(text):
yield text[match.start()]
first_letters.pattern = re_compile(r"((?<!\w)\w)|\d")
def is_upsidedown_wrong(name):
"""Tell if the string would get a different meaning if written upside down"""
chars = set(name)
mistakable = set("69NZMWpbqd")
rotatable = set("80oOxXIl").union(mistakable)
return chars.issubset(rotatable) and not chars.isdisjoint(mistakable)
def pairs(sequence):
"""Generate consecutive pairs throughout the given sequence; at last, it gives elements last, first."""
i = iter(sequence)
previous = first = next(i)
for this in i:
yield previous, this
previous = this
yield this, first
def fitting_matrix(v1, v2):
"""Get a matrix that rotates v1 to the same direction as v2"""
return (1 / v1.length_squared) * M.Matrix((
(v1.x*v2.x + v1.y*v2.y, v1.y*v2.x - v1.x*v2.y),
(v1.x*v2.y - v1.y*v2.x, v1.x*v2.x + v1.y*v2.y)))
def z_up_matrix(n):
"""Get a rotation matrix that aligns given vector upwards."""
b = n.xy.length
if b > 0:
return M.Matrix((
(n.x*n.z/(b*s), n.y*n.z/(b*s), -b/s),
(-n.y/b, n.x/b, 0),
(0, 0, 0)
))
else:
# no need for rotation
return M.Matrix((
(1, 0, 0),
(0, (-1 if n.z < 0 else 1), 0),
(0, 0, 0)
))
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def cage_fit(points, aspect):
"""Find rotation for a minimum bounding box with a given aspect ratio
returns a tuple: rotation angle, box height"""
def guesses(polygon):
"""Yield all tentative extrema of the bounding box height wrt. polygon rotation"""
for a, b in pairs(polygon):
if a == b:
continue
direction = (b - a).normalized()
sinx, cosx = -direction.y, direction.x
rot = M.Matrix(((cosx, -sinx), (sinx, cosx)))
rot_polygon = [rot @ p for p in polygon]
left, right = [fn(rot_polygon, key=lambda p: p.to_tuple()) for fn in (min, max)]
bottom, top = [fn(rot_polygon, key=lambda p: p.yx.to_tuple()) for fn in (min, max)]
horz, vert = right - left, top - bottom
# solve (rot * a).y == (rot * b).y
yield max(aspect * horz.x, vert.y), sinx, cosx
# solve (rot * a).x == (rot * b).x
yield max(horz.x, aspect * vert.y), -cosx, sinx
# solve aspect * (rot * (right - left)).x == (rot * (top - bottom)).y
# using substitution t = tan(rot / 2)
q = aspect * horz.x - vert.y
r = vert.x + aspect * horz.y
t = ((r**2 + q**2)**0.5 - r) / q if q != 0 else 0
t = -1 / t if abs(t) > 1 else t # pick the positive solution
siny, cosy = 2 * t / (1 + t**2), (1 - t**2) / (1 + t**2)
rot = M.Matrix(((cosy, -siny), (siny, cosy)))
for p in rot_polygon:
p[:] = rot @ p # note: this also modifies left, right, bottom, top
if left.x < right.x and bottom.y < top.y and all(left.x <= p.x <= right.x and bottom.y <= p.y <= top.y for p in rot_polygon):
yield max(aspect * (right - left).x, (top - bottom).y), sinx*cosy + cosx*siny, cosx*cosy - sinx*siny
polygon = [points[i] for i in M.geometry.convex_hull_2d(points)]
height, sinx, cosx = min(guesses(polygon))
return atan2(sinx, cosx), height
def create_blank_image(image_name, dimensions, alpha=1):
"""Create a new image and assign white color to all its pixels"""
image_name = image_name[:64]
width, height = int(dimensions.x), int(dimensions.y)
image = bpy.data.images.new(image_name, width, height, alpha=True)
if image.users > 0:
raise UnfoldError(
"There is something wrong with the material of the model. "
"Please report this on the BlenderArtists forum. Export failed.")
image.pixels = [1, 1, 1, alpha] * (width * height)
image.file_format = 'PNG'
return image
def store_rna_properties(*datablocks):
return [{prop.identifier: getattr(data, prop.identifier) for prop in data.rna_type.properties if not prop.is_readonly} for data in datablocks]
def apply_rna_properties(memory, *datablocks):
for recall, data in zip(memory, datablocks):
for key, value in recall.items():
setattr(data, key, value)
class UnfoldError(ValueError):
def mesh_select(self):
if len(self.args) > 1:
elems, bm = self.args[1:3]
bpy.context.tool_settings.mesh_select_mode = [bool(elems[key]) for key in ("verts", "edges", "faces")]
for elem in chain(bm.verts, bm.edges, bm.faces):
elem.select = False
for elem in chain(*elems.values()):
elem.select_set(True)
bmesh.update_edit_mesh(bpy.context.object.data, loop_triangles=False, destructive=False)
class Unfolder:
def __init__(self, ob):
self.do_create_uvmap = False
bm = bmesh.from_edit_mesh(ob.data)
self.mesh = Mesh(bm, ob.matrix_world)
self.mesh.check_correct()
def __del__(self):
if not self.do_create_uvmap:
self.mesh.delete_uvmap()
def prepare(self, cage_size=None, priority_effect=default_priority_effect, scale=1, limit_by_page=False):
"""Create the islands of the net"""
self.mesh.generate_cuts(cage_size / scale if limit_by_page and cage_size else None, priority_effect)
self.mesh.finalize_islands(cage_size or M.Vector((1, 1)))
self.mesh.enumerate_islands()
self.mesh.save_uv()
def copy_island_names(self, island_list):
"""Copy island label and abbreviation from the best matching island in the list"""
orig_islands = [{face.id for face in item.faces} for item in island_list]
matching = list()
for i, island in enumerate(self.mesh.islands):
islfaces = {face.index for face in island.faces}
matching.extend((len(islfaces.intersection(item)), i, j) for j, item in enumerate(orig_islands))
matching.sort(reverse=True)
available_new = [True for island in self.mesh.islands]
available_orig = [True for item in island_list]
for face_count, i, j in matching:
if available_new[i] and available_orig[j]:
available_new[i] = available_orig[j] = False
self.mesh.islands[i].label = island_list[j].label
self.mesh.islands[i].abbreviation = island_list[j].abbreviation
def save(self, properties):
"""Export the document"""
# Note about scale: input is directly in blender length
# Mesh.scale_islands multiplies everything by a user-defined ratio
# exporters (SVG or PDF) multiply everything by 1000 (output in millimeters)
Exporter = Svg if properties.file_format == 'SVG' else Pdf
filepath = properties.filepath
extension = properties.file_format.lower()
filepath = bpy.path.ensure_ext(filepath, "." + extension)
# page size in meters
page_size = M.Vector((properties.output_size_x, properties.output_size_y))
# printable area size in meters
printable_size = page_size - 2 * properties.output_margin * M.Vector((1, 1))
unit_scale = bpy.context.scene.unit_settings.scale_length
ppm = properties.output_dpi * 100 / 2.54 # pixels per meter
# after this call, all dimensions will be in meters
self.mesh.scale_islands(unit_scale/properties.scale)
if properties.do_create_stickers:
self.mesh.generate_stickers(properties.sticker_width, properties.do_create_numbers)
elif properties.do_create_numbers:
self.mesh.generate_numbers_alone(properties.sticker_width)
text_height = properties.sticker_width if (properties.do_create_numbers and len(self.mesh.islands) > 1) else 0
# title height must be somewhat larger that text size, glyphs go below the baseline
self.mesh.finalize_islands(printable_size, title_height=text_height * 1.2)
self.mesh.fit_islands(printable_size)
if properties.output_type != 'NONE':
# bake an image and save it as a PNG to disk or into memory
image_packing = properties.image_packing if properties.file_format == 'SVG' else 'ISLAND_EMBED'
use_separate_images = image_packing in ('ISLAND_LINK', 'ISLAND_EMBED')
self.mesh.save_uv(cage_size=printable_size, separate_image=use_separate_images)
sce = bpy.context.scene
rd = sce.render
bk = rd.bake
recall = store_rna_properties(rd, bk, sce.cycles)
rd.engine = 'CYCLES'
for p in ('color', 'diffuse', 'direct', 'emit', 'glossy', 'indirect', 'transmission'):
setattr(bk, f"use_pass_{p}", (properties.output_type != 'TEXTURE'))
lookup = {'TEXTURE': 'DIFFUSE', 'AMBIENT_OCCLUSION': 'AO', 'RENDER': 'COMBINED', 'SELECTED_TO_ACTIVE': 'COMBINED'}
sce.cycles.bake_type = lookup[properties.output_type]
bk.use_selected_to_active = (properties.output_type == 'SELECTED_TO_ACTIVE')
bk.margin, bk.cage_extrusion, bk.use_cage, bk.use_clear = 1, 10, False, False
if properties.output_type == 'TEXTURE':
bk.use_pass_direct, bk.use_pass_indirect, bk.use_pass_color = False, False, True
sce.cycles.samples = 1
if sce.cycles.bake_type == 'COMBINED':
bk.use_pass_direct, bk.use_pass_indirect = True, True
bk.use_pass_diffuse, bk.use_pass_glossy, bk.use_pass_transmission, bk.use_pass_emit = True, False, False, True
if image_packing == 'PAGE_LINK':
self.mesh.save_image(printable_size * ppm, filepath)
elif image_packing == 'ISLAND_LINK':
image_dir = filepath[:filepath.rfind(".")]
self.mesh.save_separate_images(ppm, image_dir)
elif image_packing == 'ISLAND_EMBED':
self.mesh.save_separate_images(ppm, filepath, embed=Exporter.encode_image)
apply_rna_properties(recall, rd, bk, sce.cycles)
exporter = Exporter(properties)
exporter.write(self.mesh, filepath)
class Mesh:
"""Wrapper for Bpy Mesh"""
def __init__(self, bmesh, matrix):
self.data = bmesh
self.matrix = matrix.to_3x3()
self.looptex = bmesh.loops.layers.uv.new("Unfolded")
self.edges = {bmedge: Edge(bmedge) for bmedge in bmesh.edges}
self.islands = list()
self.pages = list()
for edge in self.edges.values():
edge.choose_main_faces()
if edge.main_faces:
edge.calculate_angle()
self.copy_freestyle_marks()
def delete_uvmap(self):
self.data.loops.layers.uv.remove(self.looptex) if self.looptex else None
def copy_freestyle_marks(self):
# NOTE: this is a workaround for NotImplementedError on bmesh.edges.layers.freestyle
mesh = bpy.data.meshes.new("unfolder_temp")
self.data.to_mesh(mesh)
for bmedge, edge in self.edges.items():
edge.freestyle = mesh.edges[bmedge.index].use_freestyle_mark
bpy.data.meshes.remove(mesh)
def mark_cuts(self):
for bmedge, edge in self.edges.items():
if edge.is_main_cut and not bmedge.is_boundary:
bmedge.seam = True
def check_correct(self, epsilon=1e-6):
"""Check for invalid geometry"""
def is_twisted(face):
if len(face.verts) <= 3:
return False
center = face.calc_center_median()
plane_d = center.dot(face.normal)
diameter = max((center - vertex.co).length for vertex in face.verts)
threshold = 0.01 * diameter
return any(abs(v.co.dot(face.normal) - plane_d) > threshold for v in face.verts)
null_edges = {e for e in self.edges.keys() if e.calc_length() < epsilon and e.link_faces}
null_faces = {f for f in self.data.faces if f.calc_area() < epsilon}
twisted_faces = {f for f in self.data.faces if is_twisted(f)}
inverted_scale = self.matrix.determinant() <= 0
if not (null_edges or null_faces or twisted_faces or inverted_scale):
return True
if inverted_scale:
raise UnfoldError(
"The object is flipped inside-out.\n"
"You can use Object -> Apply -> Scale to fix it. Export failed.")
disease = [("Remove Doubles", null_edges or null_faces), ("Triangulate", twisted_faces)]
cure = " and ".join(s for s, k in disease if k)
raise UnfoldError(
"The model contains:\n" +
(" {} zero-length edge(s)\n".format(len(null_edges)) if null_edges else "") +
(" {} zero-area face(s)\n".format(len(null_faces)) if null_faces else "") +
(" {} twisted polygon(s)\n".format(len(twisted_faces)) if twisted_faces else "") +
"The offenders are selected and you can use {} to fix them. Export failed.".format(cure),
{"verts": set(), "edges": null_edges, "faces": null_faces | twisted_faces}, self.data)
def generate_cuts(self, page_size, priority_effect):
"""Cut the mesh so that it can be unfolded to a flat net."""
normal_matrix = self.matrix.inverted().transposed()
islands = {Island(self, face, self.matrix, normal_matrix) for face in self.data.faces}
uvfaces = {face: uvface for island in islands for face, uvface in island.faces.items()}
uvedges = {loop: uvedge for island in islands for loop, uvedge in island.edges.items()}
for loop, uvedge in uvedges.items():
self.edges[loop.edge].uvedges.append(uvedge)
# check for edges that are cut permanently
edges = [edge for edge in self.edges.values() if not edge.force_cut and edge.main_faces]
average_length = sum(edge.vector.length for edge in edges) / len(edges)
for edge in edges:
edge.generate_priority(priority_effect, average_length)
edges.sort(reverse=False, key=lambda edge: edge.priority)
for edge in edges:
if not edge.vector:
edge_a, edge_b = (uvedges[l] for l in edge.main_faces)
old_island = join(edge_a, edge_b, size_limit=page_size)
if old_island:
islands.remove(old_island)
self.islands = sorted(islands, reverse=True, key=lambda island: len(island.faces))
for edge in self.edges.values():
# some edges did not know until now whether their angle is convex or concave
if edge.main_faces and (uvfaces[edge.main_faces[0].face].flipped or uvfaces[edge.main_faces[1].face].flipped):
edge.calculate_angle()
# ensure that the order of faces corresponds to the order of uvedges
if edge.main_faces:
reordered = [None, None]
for uvedge in edge.uvedges:
try:
index = edge.main_faces.index(uvedge.loop)
reordered[index] = uvedge
except ValueError:
reordered.append(uvedge)
edge.uvedges = reordered
for island in self.islands:
# if the normals are ambiguous, flip them so that there are more convex edges than concave ones
if any(uvface.flipped for uvface in island.faces.values()):
island_edges = {self.edges[uvedge.edge] for uvedge in island.edges}
balance = sum((+1 if edge.angle > 0 else -1) for edge in island_edges if not edge.is_cut(uvedge.uvface.face))
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if balance < 0:
island.is_inside_out = True
# construct a linked list from each island's boundary
# uvedge.neighbor_right is clockwise = forward = via uvedge.vb if not uvface.flipped
neighbor_lookup, conflicts = dict(), dict()
for uvedge in island.boundary:
uvvertex = uvedge.va if uvedge.uvface.flipped else uvedge.vb
if uvvertex not in neighbor_lookup:
neighbor_lookup[uvvertex] = uvedge
else:
if uvvertex not in conflicts:
conflicts[uvvertex] = [neighbor_lookup[uvvertex], uvedge]
else:
conflicts[uvvertex].append(uvedge)
for uvedge in island.boundary:
uvvertex = uvedge.vb if uvedge.uvface.flipped else uvedge.va
if uvvertex not in conflicts:
# using the 'get' method so as to handle single-connected vertices properly
uvedge.neighbor_right = neighbor_lookup.get(uvvertex, uvedge)
uvedge.neighbor_right.neighbor_left = uvedge
else:
conflicts[uvvertex].append(uvedge)
# resolve merged vertices with more boundaries crossing
def direction_to_float(vector):
return (1 - vector.x/vector.length) if vector.y > 0 else (vector.x/vector.length - 1)
for uvvertex, uvedges in conflicts.items():
def is_inwards(uvedge):
return uvedge.uvface.flipped == (uvedge.va is uvvertex)
def uvedge_sortkey(uvedge):
if is_inwards(uvedge):
return direction_to_float(uvedge.va.co - uvedge.vb.co)
else:
return direction_to_float(uvedge.vb.co - uvedge.va.co)
uvedges.sort(key=uvedge_sortkey)
for right, left in (
zip(uvedges[:-1:2], uvedges[1::2]) if is_inwards(uvedges[0])
else zip([uvedges[-1]] + uvedges[1::2], uvedges[:-1:2])):
left.neighbor_right = right
right.neighbor_left = left
return True
def generate_stickers(self, default_width, do_create_numbers=True):
"""Add sticker faces where they are needed."""
def uvedge_priority(uvedge):
"""Returns whether it is a good idea to stick something on this edge's face"""
# TODO: it should take into account overlaps with faces and with other stickers
face = uvedge.uvface.face
return face.calc_area() / face.calc_perimeter()
def add_sticker(uvedge, index, target_uvedge):
uvedge.sticker = Sticker(uvedge, default_width, index, target_uvedge)
uvedge.uvface.island.add_marker(uvedge.sticker)
def is_index_obvious(uvedge, target):
if uvedge in (target.neighbor_left, target.neighbor_right):
return True
if uvedge.neighbor_left.loop.edge is target.neighbor_right.loop.edge and uvedge.neighbor_right.loop.edge is target.neighbor_left.loop.edge:
return True
return False
for edge in self.edges.values():
if edge.is_main_cut and len(edge.uvedges) >= 2 and edge.vector.length_squared > 0:
target, source = edge.uvedges[:2]
if uvedge_priority(target) < uvedge_priority(source):
target, source = source, target
target_island = target.uvface.island
if do_create_numbers:
for uvedge in [source] + edge.uvedges[2:]:
if not is_index_obvious(uvedge, target):
# it will not be clear to see that these uvedges should be sticked together
# So, create an arrow and put the index on all stickers
target_island.sticker_numbering += 1
index = str(target_island.sticker_numbering)
if is_upsidedown_wrong(index):
index += "."
target_island.add_marker(Arrow(target, default_width, index))
add_sticker(source, index, target)
elif len(edge.uvedges) > 2:
target = edge.uvedges[0]
if len(edge.uvedges) > 2:
for source in edge.uvedges[2:]:
add_sticker(source, index, target)
def generate_numbers_alone(self, size):
global_numbering = 0
for edge in self.edges.values():
if edge.is_main_cut and len(edge.uvedges) >= 2:
global_numbering += 1
index = str(global_numbering)
if is_upsidedown_wrong(index):
index += "."
for uvedge in edge.uvedges:
uvedge.uvface.island.add_marker(NumberAlone(uvedge, index, size))
def enumerate_islands(self):
for num, island in enumerate(self.islands, 1):
island.number = num
island.generate_label()
def scale_islands(self, scale):
for island in self.islands:
vertices = set(island.vertices.values())
for point in chain((vertex.co for vertex in vertices), island.fake_vertices):
point *= scale
def finalize_islands(self, cage_size, title_height=0):
for island in self.islands:
if title_height:
island.title = "[{}] {}".format(island.abbreviation, island.label)
points = [vertex.co for vertex in set(island.vertices.values())] + island.fake_vertices
angle, _ = cage_fit(points, (cage_size.y - title_height) / cage_size.x)
rot = M.Matrix.Rotation(angle, 2)
for point in points:
for marker in island.markers:
marker.rot = rot @ marker.rot
bottom_left = M.Vector((min(v.x for v in points), min(v.y for v in points) - title_height))
# DEBUG
# top_right = M.Vector((max(v.x for v in points), max(v.y for v in points) - title_height))
# print(f"fitted aspect: {(top_right.y - bottom_left.y) / (top_right.x - bottom_left.x)}")
for point in points:
point -= bottom_left
island.bounding_box = M.Vector((max(v.x for v in points), max(v.y for v in points)))
def largest_island_ratio(self, cage_size):
return max(i / p for island in self.islands for (i, p) in zip(island.bounding_box, cage_size))
def fit_islands(self, cage_size):
"""Move islands so that they fit onto pages, based on their bounding boxes"""
def try_emplace(island, page_islands, stops_x, stops_y, occupied_cache):
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"""Tries to put island to each pair from stops_x, stops_y
and checks if it overlaps with any islands present on the page.
Returns True and positions the given island on success."""
bbox_x, bbox_y = island.bounding_box.xy
for x in stops_x:
if x + bbox_x > cage_size.x:
continue
for y in stops_y:
if y + bbox_y > cage_size.y or (x, y) in occupied_cache:
continue
for i, obstacle in enumerate(page_islands):
# if this obstacle overlaps with the island, try another stop
if (x + bbox_x > obstacle.pos.x and
obstacle.pos.x + obstacle.bounding_box.x > x and
y + bbox_y > obstacle.pos.y and
obstacle.pos.y + obstacle.bounding_box.y > y):
if x >= obstacle.pos.x and y >= obstacle.pos.y:
occupied_cache.add((x, y))
# just a stupid heuristic to make subsequent searches faster
if i > 0:
page_islands[1:i+1] = page_islands[:i]
page_islands[0] = obstacle
break
else:
# if no obstacle called break, this position is okay
island.pos.xy = x, y
page_islands.append(island)
stops_x.append(x + bbox_x)
stops_y.append(y + bbox_y)
return True
return False
def drop_portion(stops, border, divisor):
stops.sort()
# distance from left neighbor to the right one, excluding the first stop
distances = [right - left for left, right in zip(stops, chain(stops[2:], [border]))]
quantile = sorted(distances)[len(distances) // divisor]
return [stop for stop, distance in zip(stops, chain([quantile], distances)) if distance >= quantile]
if any(island.bounding_box.x > cage_size.x or island.bounding_box.y > cage_size.y for island in self.islands):
raise UnfoldError(
"An island is too big to fit onto page of the given size. "
"Either downscale the model or find and split that island manually.\n"
"Export failed, sorry.")
# sort islands by their diagonal... just a guess
remaining_islands = sorted(self.islands, reverse=True, key=lambda island: island.bounding_box.length_squared)
page_num = 1 # TODO delete me
while remaining_islands:
# create a new page and try to fit as many islands onto it as possible
page = Page(page_num)
page_num += 1
occupied_cache = set()
stops_x, stops_y = [0], [0]
for island in remaining_islands:
try_emplace(island, page.islands, stops_x, stops_y, occupied_cache)
# if overwhelmed with stops, drop a quarter of them
if len(stops_x)**2 > 4 * len(self.islands) + 100:
stops_x = drop_portion(stops_x, cage_size.x, 4)
stops_y = drop_portion(stops_y, cage_size.y, 4)
remaining_islands = [island for island in remaining_islands if island not in page.islands]
self.pages.append(page)
def save_uv(self, cage_size=M.Vector((1, 1)), separate_image=False):
if separate_image:
for island in self.islands:
island.save_uv_separate(self.looptex)
else:
for island in self.islands:
island.save_uv(self.looptex, cage_size)
def save_image(self, page_size_pixels: M.Vector, filename):
for page in self.pages:
image = create_blank_image("Page {}".format(page.name), page_size_pixels, alpha=1)
image.filepath_raw = page.image_path = "{}_{}.png".format(filename, page.name)
faces = [face for island in page.islands for face in island.faces]
self.bake(faces, image)
image.save()
image.user_clear()
bpy.data.images.remove(image)
def save_separate_images(self, scale, filepath, embed=None):
for i, island in enumerate(self.islands):
image_name = "Island {}".format(i)
image = create_blank_image(image_name, island.bounding_box * scale, alpha=0)
self.bake(island.faces.keys(), image)
if embed:
island.embedded_image = embed(image)
else:
from os import makedirs
image_dir = filepath
makedirs(image_dir, exist_ok=True)
image_path = os_path.join(image_dir, "island{}.png".format(i))
image.filepath_raw = image_path
image.save()
island.image_path = image_path
image.user_clear()
bpy.data.images.remove(image)
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def bake(self, faces, image):
if not self.looptex:
raise UnfoldError("The mesh has no UV Map slots left. Either delete a UV Map or export the net without textures.")
ob = bpy.context.active_object
me = ob.data
# in Cycles, the image for baking is defined by the active Image Node
temp_nodes = dict()
for mat in me.materials:
mat.use_nodes = True
img = mat.node_tree.nodes.new('ShaderNodeTexImage')
img.image = image
temp_nodes[mat] = img
mat.node_tree.nodes.active = img
# move all excess faces to negative numbers (that is the only way to disable them)
ignored_uvs = [loop[self.looptex].uv for f in self.data.faces if f not in faces for loop in f.loops]
for uv in ignored_uvs:
uv *= -1
bake_type = bpy.context.scene.cycles.bake_type
sta = bpy.context.scene.render.bake.use_selected_to_active
try:
ob.update_from_editmode()
me.uv_layers.active = me.uv_layers[self.looptex.name]
bpy.ops.object.bake(type=bake_type, margin=1, use_selected_to_active=sta, cage_extrusion=100, use_clear=False)
except RuntimeError as e:
raise UnfoldError(*e.args)
finally:
for mat, node in temp_nodes.items():
mat.node_tree.nodes.remove(node)
for uv in ignored_uvs:
uv *= -1
class Edge:
"""Wrapper for BPy Edge"""
__slots__ = (
'data', 'va', 'vb', 'main_faces', 'uvedges',
'is_main_cut', 'force_cut', 'priority', 'freestyle')
def __init__(self, edge):
self.data = edge
self.va, self.vb = edge.verts
self.vector = self.vb.co - self.va.co
# if self.main_faces is set, then self.uvedges[:2] must correspond to self.main_faces, in their order
# this constraint is assured at the time of finishing mesh.generate_cuts
self.uvedges = list()
self.force_cut = edge.seam # such edges will always be cut
self.main_faces = None # two faces that may be connected in the island
# is_main_cut defines whether the two main faces are connected
# all the others will be assumed to be cut
self.is_main_cut = True
self.priority = None
self.angle = None
self.freestyle = False
def choose_main_faces(self):
"""Choose two main faces that might get connected in an island"""
def score(pair):
return abs(pair[0].face.normal.dot(pair[1].face.normal))
loops = self.data.link_loops
if len(loops) == 2:
self.main_faces = list(loops)
elif len(loops) > 2:
# find (with brute force) the pair of indices whose loops have the most similar normals
self.main_faces = max(combinations(loops, 2), key=score)
if self.main_faces and self.main_faces[1].vert == self.va:
self.main_faces = self.main_faces[::-1]
def calculate_angle(self):
"""Calculate the angle between the main faces"""
loop_a, loop_b = self.main_faces
normal_a, normal_b = (l.face.normal for l in self.main_faces)
if not normal_a or not normal_b:
self.angle = -3 # just a very sharp angle
s = normal_a.cross(normal_b).dot(self.vector.normalized())
s = max(min(s, 1.0), -1.0) # deal with rounding errors
if loop_a.link_loop_next.vert != loop_b.vert or loop_b.link_loop_next.vert != loop_a.vert:
self.angle = abs(self.angle)
def generate_priority(self, priority_effect, average_length):
"""Calculate the priority value for cutting"""
angle = self.angle
if angle > 0:
self.priority = priority_effect['CONVEX'] * angle / pi
else:
self.priority = priority_effect['CONCAVE'] * (-angle) / pi
self.priority += (self.vector.length / average_length) * priority_effect['LENGTH']
def is_cut(self, face):
"""Return False if this edge will the given face to another one in the resulting net
(useful for edges with more than two faces connected)"""
# Return whether there is a cut between the two main faces
if self.main_faces and face in {loop.face for loop in self.main_faces}:
return self.is_main_cut
# All other faces (third and more) are automatically treated as cut
else:
return True
def other_uvedge(self, this):
"""Get an uvedge of this edge that is not the given one
causes an IndexError if case of less than two adjacent edges"""
return self.uvedges[1] if this is self.uvedges[0] else self.uvedges[0]
class Island:
"""Part of the net to be exported"""
__slots__ = (
'mesh', 'faces', 'edges', 'vertices', 'fake_vertices', 'boundary', 'markers',
'pos', 'bounding_box',
'image_path', 'embedded_image',
'number', 'label', 'abbreviation', 'title',
'has_safe_geometry', 'is_inside_out',
'sticker_numbering')
def __init__(self, mesh, face, matrix, normal_matrix):
"""Create an Island from a single Face"""
self.mesh = mesh
self.faces = dict() # face -> uvface
self.edges = dict() # loop -> uvedge
self.vertices = dict() # loop -> uvvertex
self.fake_vertices = list()
self.markers = list()
self.label = None
self.abbreviation = None
self.title = None
self.pos = M.Vector((0, 0))
self.image_path = None
self.embedded_image = None
self.is_inside_out = False # swaps concave <-> convex edges
self.has_safe_geometry = True
self.sticker_numbering = 0
uvface = UVFace(face, self, matrix, normal_matrix)
self.vertices.update(uvface.vertices)
self.edges.update(uvface.edges)
self.faces[face] = uvface
# UVEdges on the boundary
self.boundary = list(self.edges.values())
def add_marker(self, marker):
self.fake_vertices.extend(marker.bounds)
self.markers.append(marker)
def generate_label(self, label=None, abbreviation=None):
"""Assign a name to this island automatically"""
abbr = abbreviation or self.abbreviation or str(self.number)
# TODO: dots should be added in the last instant when outputting any text
if is_upsidedown_wrong(abbr):
abbr += "."
self.label = label or self.label or "Island {}".format(self.number)
self.abbreviation = abbr
def save_uv(self, tex, cage_size):
"""Save UV Coordinates of all UVFaces to a given UV texture
tex: UV Texture layer to use (BMLayerItem)
page_size: size of the page in pixels (vector)"""
scale_x, scale_y = 1 / cage_size.x, 1 / cage_size.y
for loop, uvvertex in self.vertices.items():
uv = uvvertex.co + self.pos
loop[tex].uv = uv.x * scale_x, uv.y * scale_y
def save_uv_separate(self, tex):
"""Save UV Coordinates of all UVFaces to a given UV texture, spanning from 0 to 1
tex: UV Texture layer to use (BMLayerItem)
page_size: size of the page in pixels (vector)"""
scale_x, scale_y = 1 / self.bounding_box.x, 1 / self.bounding_box.y
for loop, uvvertex in self.vertices.items():
loop[tex].uv = uvvertex.co.x * scale_x, uvvertex.co.y * scale_y
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def join(uvedge_a, uvedge_b, size_limit=None, epsilon=1e-6):
"""
Try to join other island on given edge
Returns False if they would overlap
"""
class Intersection(Exception):
pass
class GeometryError(Exception):
pass
def is_below(self, other, correct_geometry=True):
if self is other:
return False
if self.top < other.bottom:
return True
if other.top < self.bottom:
return False
if self.max.tup <= other.min.tup:
return True
if other.max.tup <= self.min.tup:
return False
self_vector = self.max.co - self.min.co
min_to_min = other.min.co - self.min.co
cross_b1 = self_vector.cross(min_to_min)
cross_b2 = self_vector.cross(other.max.co - self.min.co)
if cross_b2 < cross_b1:
cross_b1, cross_b2 = cross_b2, cross_b1
if cross_b2 > 0 and (cross_b1 > 0 or (cross_b1 == 0 and not self.is_uvface_upwards())):
return True
if cross_b1 < 0 and (cross_b2 < 0 or (cross_b2 == 0 and self.is_uvface_upwards())):
return False
other_vector = other.max.co - other.min.co
cross_a1 = other_vector.cross(-min_to_min)
cross_a2 = other_vector.cross(self.max.co - other.min.co)
if cross_a2 < cross_a1:
cross_a1, cross_a2 = cross_a2, cross_a1
if cross_a2 > 0 and (cross_a1 > 0 or (cross_a1 == 0 and not other.is_uvface_upwards())):
return False
if cross_a1 < 0 and (cross_a2 < 0 or (cross_a2 == 0 and other.is_uvface_upwards())):
return True
if cross_a1 == cross_b1 == cross_a2 == cross_b2 == 0:
if correct_geometry:
raise GeometryError
elif self.is_uvface_upwards() == other.is_uvface_upwards():
raise Intersection
return False
if self.min.tup == other.min.tup or self.max.tup == other.max.tup:
return cross_a2 > cross_b2
raise Intersection
class QuickSweepline:
"""Efficient sweepline based on binary search, checking neighbors only"""
def __init__(self):
self.children = list()
def add(self, item, cmp=is_below):
low, high = 0, len(self.children)
while low < high:
mid = (low + high) // 2
if cmp(self.children[mid], item):
low = mid + 1
else:
high = mid
self.children.insert(low, item)
def remove(self, item, cmp=is_below):
index = self.children.index(item)
self.children.pop(index)
if index > 0 and index < len(self.children):
# check for intersection
if cmp(self.children[index], self.children[index-1]):
raise GeometryError
class BruteSweepline:
"""Safe sweepline which checks all its members pairwise"""
def __init__(self):
self.children = set()
def add(self, item, cmp=is_below):
for child in self.children:
if child.min is not item.min and child.max is not item.max:
cmp(item, child, False)
self.children.add(item)
def remove(self, item):
self.children.remove(item)
def sweep(sweepline, segments):
"""Sweep across the segments and raise an exception if necessary"""
# careful, 'segments' may be a use-once iterator
events_add = sorted(segments, reverse=True, key=lambda uvedge: uvedge.min.tup)
events_remove = sorted(events_add, reverse=True, key=lambda uvedge: uvedge.max.tup)
while events_remove:
while events_add and events_add[-1].min.tup <= events_remove[-1].max.tup:
sweepline.add(events_add.pop())
sweepline.remove(events_remove.pop())
def root_find(value, tree):
"""Find the root of a given value in a forest-like dictionary
also updates the dictionary using path compression"""
parent, relink = tree.get(value), list()
while parent is not None:
relink.append(value)
value, parent = parent, tree.get(parent)
tree.update(dict.fromkeys(relink, value))
return value
def slope_from(position):
def slope(uvedge):
vec = (uvedge.vb.co - uvedge.va.co) if uvedge.va.tup == position else (uvedge.va.co - uvedge.vb.co)
return (vec.y / vec.length + 1) if ((vec.x, vec.y) > (0, 0)) else (-1 - vec.y / vec.length)
return slope
island_a, island_b = (e.uvface.island for e in (uvedge_a, uvedge_b))
if island_a is island_b:
return False
elif len(island_b.faces) > len(island_a.faces):
uvedge_a, uvedge_b = uvedge_b, uvedge_a
island_a, island_b = island_b, island_a
# check if vertices and normals are aligned correctly
verts_flipped = uvedge_b.loop.vert is uvedge_a.loop.vert
flipped = verts_flipped ^ uvedge_a.uvface.flipped ^ uvedge_b.uvface.flipped
# determine rotation
# NOTE: if the edges differ in length, the matrix will involve uniform scaling.
# Such situation may occur in the case of twisted n-gons
first_b, second_b = (uvedge_b.va, uvedge_b.vb) if not verts_flipped else (uvedge_b.vb, uvedge_b.va)
if not flipped:
rot = fitting_matrix(first_b.co - second_b.co, uvedge_a.vb.co - uvedge_a.va.co)
else:
flip = M.Matrix(((-1, 0), (0, 1)))
rot = fitting_matrix(flip @ (first_b.co - second_b.co), uvedge_a.vb.co - uvedge_a.va.co) @ flip
trans = uvedge_a.vb.co - rot @ first_b.co
# preview of island_b's vertices after the join operation
phantoms = {uvvertex: UVVertex(rot @ uvvertex.co + trans) for uvvertex in island_b.vertices.values()}
# check the size of the resulting island
if size_limit:
points = [vert.co for vert in chain(island_a.vertices.values(), phantoms.values())]
left, right, bottom, top = (fn(co[i] for co in points) for i in (0, 1) for fn in (min, max))
bbox_width = right - left
bbox_height = top - bottom
if min(bbox_width, bbox_height)**2 > size_limit.x**2 + size_limit.y**2:
return False
if (bbox_width > size_limit.x or bbox_height > size_limit.y) and (bbox_height > size_limit.x or bbox_width > size_limit.y):
_, height = cage_fit(points, size_limit.y / size_limit.x)
if height > size_limit.y:
return False
distance_limit = uvedge_a.loop.edge.calc_length() * epsilon
# try and merge UVVertices closer than sqrt(distance_limit)
merged_uvedges = set()
merged_uvedge_pairs = list()
# merge all uvvertices that are close enough using a union-find structure
# uvvertices will be merged only in cases island_b->island_a and island_a->island_a
# all resulting groups are merged together to a uvvertex of island_a
is_merged_mine = False
shared_vertices = {loop.vert for loop in chain(island_a.vertices, island_b.vertices)}
for vertex in shared_vertices:
uvs_a = {island_a.vertices.get(loop) for loop in vertex.link_loops} - {None}
uvs_b = {island_b.vertices.get(loop) for loop in vertex.link_loops} - {None}
for a, b in product(uvs_a, uvs_b):
if (a.co - phantoms[b].co).length_squared < distance_limit:
phantoms[b] = root_find(a, phantoms)
for a1, a2 in combinations(uvs_a, 2):
if (a1.co - a2.co).length_squared < distance_limit:
a1, a2 = (root_find(a, phantoms) for a in (a1, a2))
if a1 is not a2:
phantoms[a2] = a1
is_merged_mine = True
for source, target in phantoms.items():
target = root_find(target, phantoms)
phantoms[source] = target
for uvedge in (chain(island_a.boundary, island_b.boundary) if is_merged_mine else island_b.boundary):
for loop in uvedge.loop.link_loops:
partner = island_b.edges.get(loop) or island_a.edges.get(loop)
if partner is not None and partner is not uvedge:
paired_a, paired_b = phantoms.get(partner.vb, partner.vb), phantoms.get(partner.va, partner.va)
if (partner.uvface.flipped ^ flipped) != uvedge.uvface.flipped:
paired_a, paired_b = paired_b, paired_a
if phantoms.get(uvedge.va, uvedge.va) is paired_a and phantoms.get(uvedge.vb, uvedge.vb) is paired_b:
# if these two edges will get merged, add them both to the set
merged_uvedges.update((uvedge, partner))
merged_uvedge_pairs.append((uvedge, partner))
break
if uvedge_b not in merged_uvedges:
raise UnfoldError("Export failed. Please report this error, including the model if you can.")
boundary_other = [
PhantomUVEdge(phantoms[uvedge.va], phantoms[uvedge.vb], flipped ^ uvedge.uvface.flipped)
for uvedge in island_b.boundary if uvedge not in merged_uvedges]