mesh.Mesh.partition_by_angle

Mesh.partition_by_angle(angle=60.0, sort='number')

Partition a tri3 Mesh by splitting it at sharp edges.

The Mesh is partitioned in parts in which all elements can be reached without ever crossing a sharp edge angle. More precisely, any two triangles will belong to the same part if the can be connected by a line in the surface that does not cross an edge between two elements having their normals differ more than the specified angle.

Parameters

angle: float

The minimum value of the angle (in degrees) between the normals on two adjacent triangles in order for the edge to be considered a sharp edge.

sort: str

Defines how the resulting parts are sorted (by assigning them increasing part numbers). The following sort criteria are currently defined (any other value will return the parts unsorted):

• ‘number’: sort in decreasing order of the number of triangles in the part. This is the default.

• ‘area’: sort according to decreasing surface area of the part.

Returns

int array

An int array specifying for each triangle to which part it belongs. Values are in the range 0..nparts.

Notes

Beware that the existence of degenerate elements may cause unexpected results. If unsure, use the remove_degenerate() method first to remove those elements.

Examples

>>> coords = Coords([[0.0, 0.0, 0.0],
...                  [1.0, 0.0, 0.0],
...                  [0.0, 1.0, 0.0],
...                  [0.0, 0.0, 2.0]])
>>> elems = [[0,1,2], [0,2,3]]
>>> M = Mesh(coords,elems,eltype='tri3')
>>> print(M.partition_by_angle())
[1 0]