ddg.datastructures.halfedge.surface_generator module

Module ‘surface_generator’ defines some primitive halfedge surfaces

ddg.datastructures.halfedge.surface_generator.grid(m, n, generate_coordinates=True)

Create a quadrilateral grid with m x n quadrilaterals.

By default, standard coordinates will be assigned to the vertices and can be accessed via the attribute coordinate co.

Parameters:

mint

Number of quadrilaterals in first direction.

nint

Number of quadrilaterals in second direction.

generate_coordinatesbool, optional

Decides on whether a container like coordinate attribute with default standard coordinates shall be assigned to the vertices.

Returns:

ssurface

The created quadrilateral grid.

Notes

• Coordinate attribute The coordinate attribute co assigned to the vertices is of type numpy.ndarray and contains some default standard coordinates.

ddg.datastructures.halfedge.surface_generator.triangle_grid(m, n, generate_coordinates=True, matrix=array([[1., 0., 0.], [0., 1., 0.], [0., 0., 1.]]))

Create a triangle grid with m x n triangles.

By default, standard coordinates will be assigned to the vertices and can be accessed via the attribute coordinate co.

Parameters:

mint

Number of triangles in first direction.

nint

Number of triangles in second direction.

generate_coordinatesbool

Decides on whether a container like coordinate attribute with default standard coordinates shall be assigned to the vertices.

matrixnumpy.ndarray

Standard coordinates get multiplied by this matrix.

Returns:

ssurface

The created triangle grid.

Notes

• Coordinate attribute The coordinate attribute co assigned to the vertices is of type numpy.ndarray and contains some default standard coordinates.

ddg.datastructures.halfedge.surface_generator.tetrahedron(generate_coordinates=True)

Creates a tetrahedron.

By default, standard coordinates of a unit tetrahedron will be assigned to the vertices and can be accessed via the attribute coordinate co.

Parameters:

generate_coordinatesbool

Decides on whether a container like coordinate attribute with default standard coordinates shall be assigned to the vertices.

Returns:

ssurface

The tetrahedron that has been created.

Notes

• Coordinate attribute The coordinate attribute co assigned to the vertices is of type numpy.ndarray and contains the standard coordinates of a unit tetrahedron.

ddg.datastructures.halfedge.surface_generator.cube(generate_coordinates=True)

Creates a cube.

By default, standard coordinates of a unit cube will be assigned to the vertices and can be accessed via the attribute coordinate co.

Parameters:

generate_coordinatesbool

Decides on whether a container like coordinate attribute with default standard coordinates shall be assigned to the vertices.

Returns:

csurface

The cube that has been created.

Notes

• Coordinate attribute The coordinate attribute co assigned to the vertices is of type numpy.ndarray and contains the standard coordinates of a unit cube.

ddg.datastructures.halfedge.surface_generator.octahedron()

Creates a octahedron.

By default, standard coordinates of a unit octahedron, centered at [0,0,0], will be assigned to the vertices and can be accessed via the attribute coordinate co.

Returns:

ssurface

The octahedron that has been created.

Notes

• Coordinate attribute The coordinate attribute co assigned to the vertices is of type numpy.ndarray and contains the standard coordinates of a unit octahedron.

ddg.datastructures.halfedge.surface_generator.dodecahedron()

Creates a dodecahedron.

By default, standard coordinates of a unit dodecahedron, centered at [0, 0, 0], will be assigned to the vertices and can be accessed via the attribute coordinate co.

Returns:

ssurface

The dodecahedron that has been created.

Notes

• Coordinate attribute The coordinate attribute co assigned to the vertices is of type numpy.ndarray and contains the standard coordinates of a unit dodecahedron.

ddg.datastructures.halfedge.surface_generator.icosahedron()

Creates a icosahedron.

By default, standard coordinates of a unit icosahedron, centered at [0, 0, 0], will be assigned to the vertices and can be accessed via the attribute coordinate co.

Returns:

ssurface

The icosahedron that has been created.

Notes

• Coordinate attribute The coordinate attribute co assigned to the vertices is of type numpy.ndarray and contains the standard coordinates of a unit icosahedron.

ddg.datastructures.halfedge.surface_generator.icosphere(subdivision_steps=1, radius=1, generate_coordinates=True)

Creates an icosphere.

By default, standard coordinates of a unit icosphere, centered at [0, 0, 0], will be assigned to the vertices and can be accessed via the attribute coordinate co.

Parameters:

subdivision_stepsint

Number of subdivisions performed, e.g. 0 for the icosahedron, 1 to subdivide each face of the icosahedron into 4 triangles, 2 to subdivide each face of the icosahedron into 16 triangles and so on.

radiusfloat

radius of the icosphere

generate_coordinatesbool

If true, generate coordinates for the icosphere, otherwise don’t generate coordinates.

Returns:

ssurface

The icosphere.

Notes

• Coordinate attribute The coordinate attribute co assigned to the vertices is of type numpy.ndarray and contains the standard coordinates of a unit icosphere.

ddg.datastructures.halfedge.surface_generator.convexhull_3d(A, join_coplanar_triangles=True)

Creates a halfedge surface of the convex hull of the input points.

Parameters:

Aarray

Input array of 3 dimensional coordinates of the form [ , , ] Dimension of the input points has to be three, i.e. non planar.

join_coplanar_trianglesTrue

If set to True, planar faces will stay triangulated. Otherwise the triangulation will be removed and result in one bigger face.

Returns:

ssurface

The convex hull that has been created.

Notes

• Coordinate attribute The coordinate attribute co assigned to the vertices is of type numpy.ndarray and contains the coordinates of the input.

ddg.datastructures.halfedge.surface_generator.arrow(resolution=20, generate_coordinates=True, levels=[[0, 0.05], [0.7, 0.05], [0.7, 0.125], 1])

Create an arrow.

By default the the bottom of the arrow is at (0,0,0), it point in the z direction, and has unit length.

Parameters:

resolutionint (default=10)

Number of vertices around the center of rotation. Minimum is 3.

generate_coordinatesbool (default=True)

If true, generate coordinates for the icosphere, otherwise don’t generate coordinates.

levelslist (default=[[0,0.05],[0.7,0.05],[0.7,0.125],1])

A 4-elements list defining the coordinates. The first three elements define the bottom, the top of the stick and the bas of the head. This three must be a 2-elements list reprensenting the height and the radius. The last element defines the height of the peak of the head.

Returns:

ssurface

The arrow.

Notes

• Coordinate attribute The coordinate attribute co assigned to the vertices is of type numpy.ndarray and contains the coordinates of the input.

ddg.datastructures.halfedge.surface_generator.cylinder(resolution=20, fill_caps=True, generate_coordinates=True, top_radius=1, bot_radius=1, length=1, co_attr='co')

Creates a halfedge cylinder aligned along the y-axis.

Parameters:

resolution: int (default=20)

Number of faces around the cylinder

fill_caps: bool (default=True)

If True, faces are added at the ends of the cylinder.

generate_coordinates: bool (default=True)

If True, standard coordinates are set to co_attr.

top_radius: float (default=1)

Size of the top of the cylinder, located at (0, length, 0).

bot_radius: float (default=1)

Size of the bottom of the cylinder, located at (0, 0, 0).

length: float (default=1)

Size length of the cylinder along its axis.

co_attr: str (default=’co’)

If generate_coordinates is given this is the name of the vertex attribute storing the coordinates.

Returns:

The halfedge cylinder.

ddg.datastructures.halfedge.surface_generator.disc(circle_subdivisions=20, generate_coordinates=True, fill_face=True, center=None, normal=None, radius=1, co_attr='co')

Create a 2-dimensional half-edge circle or disc in 3-dimensional space as a loop of half-edges.

Parameters:

circle_subdivisions: int (default=20)

Number of vertices on the boundary of the circle or disc.

generate_coordinates: bool (default=True)

If True, coordinates are generated and assigned to the vertices as an attribute with the given co_attr name. They depend on center, normal and radius. If False, the half-edge disc is purely combinatoric.

fill_face: bool (default=True)

Bool to distinguish whether to fill the edge loop with a face or not, i.e. whether to create a disc or a circle

center: integrable of three floats (default=None)

Center of the circle. Only used if generate_coordinates=True. None defaults to np.array([0, 0, 0]).

normal: integrable of three floats (default=None)

Normal of the circle. Only used if generate_coordinates=True. None defaults to np.array([0, 0, 1]).

radius: float (default=1)

Radius of the circle. Only used if generate_coordinates=True.

co_attr: string (default=’co’)

Name of the vertex attribute that stores the coordinates. Only used if generate_coordinates=True. Depends on center, normal and radius.

Returns:

ddg.halfedge.Surface