Web - mesh of edges

class Web(points=None, edges=None, tracks=None, groups=None, options=None)

set of bipoint edges, used to represent wires this definition is very close to the definition of Mesh, but with edges instead of triangles

Note

a Wire instance can contain non-connex geometries (like many separated outlines, called islands), or even non-linear meshing (like intersecting curves). In the purpose of part design, many functions may need more regular characteristics, so checking methods exists and it is up to the user to ensure the mesh do provide them when calling the demanding functions

points

typedlist of vec3 for points

edges

typedlist of couples for edges, the couple is oriented (meanings of this depends on the usage)

tracks

typedlist of integers giving the group each line belong to

groups

custom information for each group

options

custom informations for the entire web

special methods

__add__(other)

return a new mesh concatenating the faces and points of both meshes

__iadd__(other)

append the faces and points of the other mesh

data management

own(**kwargs) → Self

Return a copy of the current mesh, which attributes are referencing the original data or duplicates if demanded

Example

>>> b = a.own(points=True, faces=False)
>>> b.points is a.points
False
>>> b.faces is a.faces
True

option(**kwargs) → self

Update the internal options with the given dictionary and the keywords arguments. This is only a shortcut to set options in a method style.

transform(trans) → Self

Apply the transform to the points of the mesh, returning the new transformed mesh

mergeclose(limit=None) → dict

Merge points below the specified distance, or below the precision return a dictionary of points remapping {src index: dst index}

O(n) implementation thanks to hashing

mergepoints(merges) → self

merge points with the merge dictionnary {src index: dst index} merged points are not removed from the buffer.

mergegroups(defs=None, merges=None) → self

Merge the groups according to the merge dictionary The new groups associated can be specified with defs The former unused groups are not removed from the buffer and the new ones are appended

If merges is not provided, all groups are merged, and defs is the data associated to the only group after the merge

strippoints() → list

remove points that are used by no faces, return the reindex list. if used is provided, these points will be removed without usage verification

return a table of the reindex made

stripgroups() → list

Remove groups that are used by no faces. return the reindex list.

finish() → self

Finish and clean the mesh

note that this operation can cost as much as other transformation operation job done

• mergeclose
• strippoints
• stripgroups
• check

mesh checks

check()

check that the internal data references are good (indices and list lengths)

isvalid()

Return true if the internal data is consistent (all indices referes to actual points and groups)

isline()

true if each point is used at most 2 times by edges

isloop()

true if the wire form a loop

selection methods

pointnear(point: dvec3) → int

Return the nearest point the the given location

pointat(point: dvec3, neigh=1e-13) → int

Return the index of the first point at the given location, or None

groupnear(point: dvec3) → int

return group id if the edge the closest to the given point

edgenear(point: dvec3) → int

return the index of the closest edge to the given point

group(quals) → Self

extract a part of the mesh corresponding to the designated groups.

Groups can be be given in either the following ways:

• a set of group indices

  This can be useful to combine with other functions. However it can be difficult for a user script to keep track of which index correspond to which created group

• an iterable of group qualifiers

  This is the best way to designate groups, and is meant to be used in combination with self.qual(). This mode selects every group having all the input qualifiers

Example

>>> # create a mesh with only the given groups
>>> mesh.group({1, 3, 8, 9})
<Mesh ...>

>>> # create a mesh with all the groups having the following qualifiers
>>> mesh.group(['extrusion', 'arc'])
<Mesh ...>

replace(mesh, groups=None) → self

replace the given groups by the given mesh. If groups is not specified, it will take the matching groups (with same index) in the current mesh

qualify(*quals, select=None, replace=False) → self

Set a new qualifier for the given groups

Parameters:

• quals – the qualifiers to enable for the selected mesh groups
• select (iterable) – if specified, only the groups having all those qualifiers will be added the new qualifiers
• replace (bool) – if True, the qualifiers in select will be removed

Example

>>> pool = meshb.qualify('part-a') + meshb.qualify('part-b')
>>> set(meshb.faces) == set(pool.group('part-b').faces)
True

>>> chamfer(mesh, ...).qualify('my-group', select='chamfer', replace=True)
>>> mesh.group('my-group')
<Mesh ...>

qualified_indices(quals)

Yield the faces indices when their associated group are matching the requirements

qualified_groups(quals)

Yield the groups indices when they are matching the requirements

extraction methods

maxnum() → float

Maximum numeric value of the mesh, use this to get an hint on its size or to evaluate the numeric precision

precision(propag=3) → float

Numeric coordinate precision of operations on this mesh, allowed by the floating point precision

length() → float

total length of edges

surface() → float

return the surface enclosed by the web if planar and is composed of loops (else it has no meaning)

barycenter() → dvec3

curve barycenter of the mesh

barycenter_points() → dvec3

Barycenter of points used

box() → Box

Return the extreme coordinates of the mesh (vec3, vec3)

usepointat(point, neigh=1e-13) → int

Return the index of the first point in the mesh at the location. If none is found, insert it and return the index

edgepoints(e) → tuple

tuple of the points for edge e

the edge can be given using its index in self.edges or using a tuple of point idinces

edgedirection(e) → dvec3

direction of edge e

the edge can be given using its index in self.edges or using a tuple of point idinces

extremities() → set

return the points that are used once only (so at wire terminations) 1D equivalent of Mesh.outlines()

groupextremities() → Wire

return the extremities of each group. 1D equivalent of Mesh.groupoutlines()

On a frontier between multiple groups, there is as many points as groups, each associated to a group.

frontiers(*args) → Wire

return a Wire of points that split the given groups appart.

The arguments are groups indices or lists of group qualifiers (as set in qualify()). If there is one only argument it is considered as as list of arguments.

• if no argument is given, then return the frontiers between every groups
• to include the groups extremities that are on the group border but not at the frontier with an other group, add None to the group set

Example

>>> w = Web([...], [uvec2(0,1), uvec2(1,2)], [0, 1], [...])
>>> w.frontiers(0,1).indices
[1]

>>> # equivalent to
>>> w.frontiers({0,1}).indices
[1]

>>> w.frontiers(0,None).indices
[0]

arcs() → [Wire]

return the contiguous portions of this web

islands() → [Web]

return the unconnected parts of the mesh as several meshes

groupislands() → Web

return the same web but with a new group each island

segmented(group=None) → Web

return a copy of the mesh with a group each edge

if group is specified, it will be the new definition put in each groups

flip() → Web

reverse direction of all edges