small change in paperfold

This commit is contained in:
Mario Voigt 2021-08-22 23:05:56 +02:00
parent b11ee2f93a
commit 5790a0f5ed
1 changed files with 71 additions and 64 deletions

View File

@ -55,7 +55,8 @@ class Paperfold(inkex.EffectExtension):
# Compute the third point of a triangle when two points and all edge lengths are given
def getThirdPoint(self, v0, v1, l01, l12, l20):
v2rotx = (l01 ** 2 + l20 ** 2 - l12 ** 2) / (2 * l01)
v2roty0 = np.sqrt((l01 + l20 + l12) * (l01 + l20 - l12) * (l01 - l20 + l12) * (-l01 + l20 + l12)) / (2 * l01)
val = (l01 + l20 + l12) * (l01 + l20 - l12) * (l01 - l20 + l12) * (-l01 + l20 + l12)
v2roty0 = np.sqrt(abs(val)) / (2 * l01)
v2roty1 = - v2roty0
@ -134,16 +135,20 @@ class Paperfold(inkex.EffectExtension):
def unfoldSpanningTree(self, mesh, spanningTree):
try:
unfoldedMesh = om.TriMesh() # the unfolded mesh
numFaces = mesh.n_faces()
sizeTree = spanningTree.number_of_edges()
numUnfoldedEdges = 3 * numFaces - sizeTree
isFoldingEdge = np.zeros(numUnfoldedEdges, dtype=bool) # Indicates whether an edge is folded or cut
glueNumber = np.empty(numUnfoldedEdges, dtype=int) # Saves with which edge is glued together
dihedralAngles = np.empty(numUnfoldedEdges, dtype=float) # Valley folding or mountain folding
connections = np.empty(numFaces, dtype=int) # Saves which original triangle belongs to the unrolled one
numFaces = mesh.n_faces()
sizeTree = spanningTree.number_of_edges()
numUnfoldedEdges = 3 * numFaces - sizeTree
# Select the first triangle as desired
startingNode = list(spanningTree.nodes())[0]
startingTriangle = mesh.face_handle(startingNode)
@ -218,65 +223,68 @@ class Paperfold(inkex.EffectExtension):
# We walk through the tree
for dualEdge in nx.dfs_edges(spanningTree, source=startingNode):
foldingEdge = mesh.edge_handle(spanningTree[dualEdge[0]][dualEdge[1]]['idx'])
# Find the corresponding half edge in the output triangle
foldingHalfEdge = mesh.halfedge_handle(foldingEdge, 0)
if not (mesh.face_handle(foldingHalfEdge).idx() == dualEdge[0]):
foldingHalfEdge = mesh.halfedge_handle(foldingEdge, 1)
# Find the corresponding unwound half edge
unfoldedLastHalfEdge = unfoldedMesh.halfedge_handle(halfEdgeConnections[foldingHalfEdge.idx()])
# Find the point in the unrolled triangle that is not on the folding edge
oppositeUnfoldedVertex = unfoldedMesh.to_vertex_handle(unfoldedMesh.next_halfedge_handle(unfoldedLastHalfEdge))
# We turn the half edges over to lie in the new triangle
foldingHalfEdge = mesh.opposite_halfedge_handle(foldingHalfEdge)
unfoldedLastHalfEdge = unfoldedMesh.opposite_halfedge_handle(unfoldedLastHalfEdge)
# The two corners of the folding edge
unfoldedFromVertex = unfoldedMesh.from_vertex_handle(unfoldedLastHalfEdge)
unfoldedToVertex = unfoldedMesh.to_vertex_handle(unfoldedLastHalfEdge)
# Calculate the edge lengths in the new triangle
secondHalfEdgeInFace = mesh.next_halfedge_handle(foldingHalfEdge)
thirdHalfEdgeInFace = mesh.next_halfedge_handle(secondHalfEdgeInFace)
originalHalfEdges = [foldingHalfEdge, secondHalfEdgeInFace, thirdHalfEdgeInFace]
edgelengths = [mesh.calc_edge_length(foldingHalfEdge), mesh.calc_edge_length(secondHalfEdgeInFace),
mesh.calc_edge_length(thirdHalfEdgeInFace)]
# We calculate the two possibilities for the third point in the triangle
[newUnfoldedVertex0, newUnfoldedVertex1] = self.getThirdPoint(unfoldedMesh.point(unfoldedFromVertex),
unfoldedMesh.point(unfoldedToVertex), edgelengths[0],
edgelengths[1], edgelengths[2])
newUnfoldedVertex = unfoldedMesh.add_vertex(newUnfoldedVertex0)
# Make the face
newface = unfoldedMesh.add_face(unfoldedFromVertex, unfoldedToVertex, newUnfoldedVertex)
secondUnfoldedHalfEdge = unfoldedMesh.next_halfedge_handle(unfoldedLastHalfEdge)
thirdUnfoldedHalfEdge = unfoldedMesh.next_halfedge_handle(secondUnfoldedHalfEdge)
unfoldedHalfEdges = [unfoldedLastHalfEdge, secondUnfoldedHalfEdge, thirdUnfoldedHalfEdge]
# Saving the information about edges and page
# Dotted one's in the output
unfoldedLastEdge = unfoldedMesh.edge_handle(unfoldedLastHalfEdge)
isFoldingEdge[unfoldedLastEdge.idx()] = True
# Gluing number and folding direction
self.addVisualisationData(mesh, unfoldedMesh, originalHalfEdges, unfoldedHalfEdges, glueNumber, dihedralAngles)
# Related page
connections[newface.idx()] = dualEdge[1]
# Identify the half edges
for i in range(3):
halfEdgeConnections[originalHalfEdges[i].idx()] = unfoldedHalfEdges[i].idx()
try:
foldingEdge = mesh.edge_handle(spanningTree[dualEdge[0]][dualEdge[1]]['idx'])
# Find the corresponding half edge in the output triangle
foldingHalfEdge = mesh.halfedge_handle(foldingEdge, 0)
if not (mesh.face_handle(foldingHalfEdge).idx() == dualEdge[0]):
foldingHalfEdge = mesh.halfedge_handle(foldingEdge, 1)
# Find the corresponding unwound half edge
unfoldedLastHalfEdge = unfoldedMesh.halfedge_handle(halfEdgeConnections[foldingHalfEdge.idx()])
# Find the point in the unrolled triangle that is not on the folding edge
oppositeUnfoldedVertex = unfoldedMesh.to_vertex_handle(unfoldedMesh.next_halfedge_handle(unfoldedLastHalfEdge))
# We turn the half edges over to lie in the new triangle
foldingHalfEdge = mesh.opposite_halfedge_handle(foldingHalfEdge)
unfoldedLastHalfEdge = unfoldedMesh.opposite_halfedge_handle(unfoldedLastHalfEdge)
# The two corners of the folding edge
unfoldedFromVertex = unfoldedMesh.from_vertex_handle(unfoldedLastHalfEdge)
unfoldedToVertex = unfoldedMesh.to_vertex_handle(unfoldedLastHalfEdge)
# Calculate the edge lengths in the new triangle
secondHalfEdgeInFace = mesh.next_halfedge_handle(foldingHalfEdge)
thirdHalfEdgeInFace = mesh.next_halfedge_handle(secondHalfEdgeInFace)
originalHalfEdges = [foldingHalfEdge, secondHalfEdgeInFace, thirdHalfEdgeInFace]
edgelengths = [mesh.calc_edge_length(foldingHalfEdge), mesh.calc_edge_length(secondHalfEdgeInFace),
mesh.calc_edge_length(thirdHalfEdgeInFace)]
# We calculate the two possibilities for the third point in the triangle
[newUnfoldedVertex0, newUnfoldedVertex1] = self.getThirdPoint(unfoldedMesh.point(unfoldedFromVertex),
unfoldedMesh.point(unfoldedToVertex), edgelengths[0],
edgelengths[1], edgelengths[2])
newUnfoldedVertex = unfoldedMesh.add_vertex(newUnfoldedVertex0)
# Make the face
newface = unfoldedMesh.add_face(unfoldedFromVertex, unfoldedToVertex, newUnfoldedVertex)
secondUnfoldedHalfEdge = unfoldedMesh.next_halfedge_handle(unfoldedLastHalfEdge)
thirdUnfoldedHalfEdge = unfoldedMesh.next_halfedge_handle(secondUnfoldedHalfEdge)
unfoldedHalfEdges = [unfoldedLastHalfEdge, secondUnfoldedHalfEdge, thirdUnfoldedHalfEdge]
# Saving the information about edges and page
# Dotted one's in the output
unfoldedLastEdge = unfoldedMesh.edge_handle(unfoldedLastHalfEdge)
isFoldingEdge[unfoldedLastEdge.idx()] = True
# Gluing number and folding direction
self.addVisualisationData(mesh, unfoldedMesh, originalHalfEdges, unfoldedHalfEdges, glueNumber, dihedralAngles)
# Related page
connections[newface.idx()] = dualEdge[1]
# Identify the half edges
for i in range(3):
halfEdgeConnections[originalHalfEdges[i].idx()] = unfoldedHalfEdges[i].idx()
except Exception as e:
inkex.utils.debug("Error walking the dual tree at dualEdge {}".format(e))
exit(1)
return [unfoldedMesh, isFoldingEdge, connections, glueNumber, dihedralAngles]
except Exception as e:
inkex.utils.debug("Error: model could not be unfolded. Check for:")
@ -286,7 +294,6 @@ class Paperfold(inkex.EffectExtension):
inkex.utils.debug(" - missing units")
inkex.utils.debug(" - missing coordinate system")
inkex.utils.debug(" - multiple bodies in one file")
inkex.utils.debug("error was: " + str(e))
exit(1)