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triellipt.trimesh

Triangle mesh object.

TriMesh

class triellipt.trimesh.TriMesh(points=None, triangs=None)

Triangle mesh.

Attributes

points : flat-complex-array

Mesh points in a complex plane.

triangs : 3-column-int-table

Triangles vertices in CCW order.

Properties

Name	Description
triu	Generator of triplot arguments.
points2d	Mesh points as two float rows.
centrs2d	Triangle centers as two float rows.

submesh()

TriMesh.submesh(self, *trinums)

Extracts a submesh.

Parameters

trinums : *int

Numbers of triangles to include.

Returns

TriMesh

New mesh object.

deltriangs()

TriMesh.deltriangs(self, *trinums)

Removes triangles from the mesh.

Parameters

trinums : *int

Numbers of triangles to delete.

Returns

TriMesh

New mesh object.

delghosts()

TriMesh.delghosts(self)

Removes ghost points from the mesh.

Returns

TriMesh

New mesh.

Notes

Related methods:

• .hasghosts() shows if there are any ghosts
• .getghosts() returns ghost numbers, if any

getvoids()

TriMesh.getvoids(self)

Finds empty triangles (voids).

Returns

flat-int-array

Numbers of empty triangles.

Notes

Related methods:

• .hasvoids() shows if there are any voids
• .delvoids() deletes voids from the mesh

alignnodes()

TriMesh.alignnodes(self, *anchors)

Performs the edge-core ordering of the mesh nodes.

Parameters

anchors : *(float, float)

Points to synchronize the mesh boundary.

Returns

TriMesh | None

New mesh, or None if the mesh boundary can not be fetched.

renumed()

TriMesh.renumed(self, permuter)

Renumbers the mesh nodes.

Parameters

permuter : flat-int-array

Permutation of mesh nodes.

Returns

TriMesh

New mesh with the nodes renumbered.

meshedge()

TriMesh.meshedge(self)

Extracts the mesh edge.

Returns

MeshEdge

Mesh edge object.

edgesmap()

TriMesh.edgesmap(self)

Maps inner mesh edges.

Returns

EdgesMap

Map of inner mesh edges.

nodesmap()

TriMesh.nodesmap(self)

Maps nodes to hosting triangles.

Returns

NodesMap

Nodes-to-triangles map.

supertriu()

TriMesh.supertriu(self)

Creates a super triangulation.

Returns

SuperTriu

Super triangulation object.

reduced()

TriMesh.reduced(self, shrink=None, detach=False, seed=None)

Tries to compress the mesh.

Parameters

shrink : int = None

Controls shrinking of super-triangulations (i).

detach : bool = False

Runs the edge detachment before compression, if True.

seed : (float, float) = None

Seed point to start reduction.

Returns

TriMesh

New mesh.

Notes

(i) Number of shrinking steps after one compression event.

scaled()

TriMesh.scaled(self, xcoeff, ycoeff)

Scales the mesh points by the specified parameters.

Parameters

xcoeff : float

Scale factor for the x-coordinate.

ycoeff : float

Scale factor for the y-coordinate.

Returns

TriMesh

New mesh with the nodes scaled.

split()

TriMesh.split(self)

Splits the mesh into homogeneous parts.

Returns

list

List of homogeneous submeshes.

MeshEdge

class triellipt.trimesh.MeshEdge(mesh=None, data=None)

Mesh edge object.

Properties

Primary data:

Name	Description
trinums	Host triangles (HT) across edges.
locnums	Local numbers of edges in HTs

Nodes numbers:

Name	Description
nodnums1	Start nodes across edges.
nodnums2	End nodes across edges.
nodnums3	Apexes across edges.

Tables:

Name	Description
edges2d	Edges as two rows of nodes numbers.
nodes2d	Start nodes positions as two float rows.

Unique values:

Name	Description
nodnums_unique	Unique numbers of edge points.
trinums_unique	Unique numbers of edge triangles.

getloops()

MeshEdge.getloops(self)

Splits the mesh edge into loops.

Returns

list

A list of EdgeLoop objects.

EdgeLoop

class triellipt.trimesh.EdgeLoop(mesh=None, data=None)

Loop on the mesh edge.

• Inherits MeshEdge properties.
• Nodes are oriented in CCW order.

synctoedge()

EdgeLoop.synctoedge(self, edgeind)

Synchronizes to the specified segment.

Parameters

edgeind : int

Index of the segment to synchronize to.

Returns

EdgeLoop

New loop.

synctonode()

EdgeLoop.synctonode(self, nodenum)

Synchronizes to the specified node.

Parameters

nodenum : int

Global node number to synchronize to.

Returns

EdgeLoop

New loop.

EdgesMap

class triellipt.trimesh.EdgesMap(mesh=None, data=None)

Map of inner mesh edges.

Properties

Name	Description
trinums1	Host triangle one (T1).
trinums2	Host triangle two (T2).
locnums1	Local edge number in T1.
locnums2	Local edge number in T2.

getspec()

EdgesMap.getspec(self)

Classifies triangles based on edges pairing.

Returns

dict

Triangles numbers for each category (i).

Notes

(i) Triangles categories:

• "heads" — 1 pair
• "links" — 2 pairs
• "cores" — 3 pairs
• "spots" — 0 pairs

NodesMap

class triellipt.trimesh.NodesMap(mesh=None, data=None)

Nodes-to-triangles map.

Properties

Nodes data:

Name	Description
nodnums	Global numbers.
trinums	Host triangles (HTs).
locnums	Local numbers in HTs.

Neighbors local numbers:

Name	Description
locnums1	Next CCW node.
locnums2	Next-next CCW node.

Neighbors global numbers:

Name	Description
nodnums1	Next CCW node.
nodnums2	Next-next CCW node.

atrank()

NodesMap.atrank(self, rank)

Extracts data for nodes with the specified rank.

Parameters

rank : int

Rank of the nodes to extract.

Returns

tuple

Triplet (nodnums, trinums, locnums) for the extracted nodes.

atnode()

NodesMap.atnode(self, nodenum)

Extracts the map of a single node.

Parameters

nodenum : int

Number of the target node.

Returns

NodesMap

The resulting single-node map.

SuperTriu

class triellipt.trimesh.SuperTriu(mesh=None, data=None)

Super triangulation.

Properties

• Hosts are background triangles with three neighbors.
• Super-triangles are made from apexes of hosts neighbors.

General:

Name	Description
trinums	Numbers of host triangles.
kermesh	Submesh of host triangles.
supmesh	Mesh from super-vertices.

Neighbors:

Name	Description
trinums1	1st CCW neighbor.
trinums2	2nd CCW neighbor.
trinums3	3rd CCW neighbor.

Super-vertices:

Name	Description
nodnums1	1st CCW vertex.
nodnums2	2nd CCW vertex.
nodnums3	3rd CCW vertex.

Notes

Non-standard nodes pairing for supmesh-kermesh transition:

• (0, 1) → 1
• (1, 2) → 2
• (2, 0) → 0

strip()

SuperTriu.strip(self)

Remove links from a super-triangulation.

Notes

See EdgesMap.getspec() for links definition.

smooth()

SuperTriu.smooth(self, iterate=True)

Removes heads and spots from a super-triangulation.

Parameters

iterate : bool = True

Runs smoothing until possible, if True.

Notes

See EdgesMap.getspec() for heads and spots definition.

detach()

SuperTriu.detach(self)

Removes super-triangles touching the background mesh edge.

reduce()

SuperTriu.reduce(self, seed=None, iterate=True)

Extracts a compact super-triangulation, if possible.

Parameters

seed : (float, float) = None

Seed point to start reduction (b).

iterate : bool = True

Triggers cleaning and retry in case of failure (a).

Returns

SuperTriu | None

Compact super-triangulation or None, if failed.

Notes

(a) Cleaning is a strip-and-smooth action.

(b) First super-triangle is used by default.

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