colour.geometry.hull_section

colour.geometry.hull_section(hull: trimesh.Trimesh, axis: Literal['+z', '+x', '+y'] | str = '+z', origin: float = 0.5, normalise: bool = False) → NDArrayFloat

Compute the hull section for the specified axis at the specified origin.

Generate a cross-sectional contour of a 3D hull by intersecting it with a plane perpendicular to the specified axis at the specified origin coordinate. This operation produces vertices that define the boundary of the hull’s intersection with the cutting plane.

Parameters:

• hull (trimesh.Trimesh) – Trimesh hull object representing the 3D geometry to section.

• axis (Literal['+z', '+x', '+y'] | str) – Axis perpendicular to which the hull section will be computed. Options are “+x”, “+y”, or “+z”.

• origin (float) – Coordinate along axis at which to compute the hull section. The value represents either an absolute position or a normalised position depending on the normalise parameter.

• normalise (bool) – Whether to normalise the origin coordinate to the extent of the hull along the specified axis. When True, origin is interpreted as a value in [0, 1] where 0 represents the minimum extent and 1 represents the maximum extent along axis.

Returns:

Hull section vertices forming a closed contour. The vertices are ordered to form a continuous path around the section boundary.

Return type:

numpy.ndarray

Raises:

ValueError – If no section exists on the specified axis at the specified origin, typically when the cutting plane does not intersect the hull.

Examples

>>> from colour.geometry import primitive_cube
>>> from colour.utilities import is_trimesh_installed
>>> vertices, faces, outline = primitive_cube(1, 1, 1, 2, 2, 2)
>>> if is_trimesh_installed:
...     import trimesh
...
...     hull = trimesh.Trimesh(vertices["position"], faces, process=False)
...     hull_section(hull, origin=0)
array([[-0. , -0.5,  0. ],
       [ 0.5, -0.5,  0. ],
       [ 0.5,  0. , -0. ],
       [ 0.5,  0.5, -0. ],
       [-0. ,  0.5,  0. ],
       [-0.5,  0.5,  0. ],
       [-0.5,  0. , -0. ],
       [-0.5, -0.5, -0. ],
       [-0. , -0.5,  0. ]])