3d_meshes.py

def generate_3D_path_meshes_2D(path, p=(0, 0, 1)):
    """Generates list of mesh vertices and triangles from a path

    Parameters
    ----------
    path : (N, D) array
        Vertices specifying the path where D is 2 or 3.
    p : 3-tuple, optional
        orthogonal vector for segment calculation in 3D.

    Returns
    ----------
    centers : (4N-4, D) array
        Vertices of all triangles for the lines
    offsets : (4N-4, D) array
        offsets of all triangles for the lines
    triangles : (2N-2, 3) array
        Vertex indices that form the mesh triangles
    """
    ndim = path.shape[1]

    centers = np.repeat(path, 4, axis=0)[2:-2]
    offsets = segment_normal(path[:-1, :], path[1:, :], p=p)
    offsets = np.repeat(offsets, 4, axis=0)
    signs = np.ones((len(offsets), ndim))
    signs[::2] = -1
    offsets = offsets * signs
    triangles = np.array(
        [
            [2 * i, 2 * i + 1, 2 * i + 2]
            if i % 2 == 0
            else [2 * i - 1, 2 * i, 2 * i + 1]
            for i in range(2 * len(path) - 2)
        ]
    ).astype(np.uint32)

    return centers, offsets, triangles


def generate_3D_path_meshes(path):
    """Generates list of mesh vertices and triangles from a path

    Parameters
    ----------
    path : (N, D) array
        Vertices specifying the path where D is 2 or 3.

    Returns
    ----------
    centers : (4N-4, D) array
        Vertices of all triangles for the lines
    offsets : (4N-4, D) array
        offsets of all triangles for the lines
    triangles : (2N-2, 3) array
        Vertex indices that form the mesh triangles
    """
    ndim = path.shape[1]
    if ndim == 2:
        centers, offsets, triangles = generate_3D_path_meshes_2D(path)
    else:
        c_a, o_a, t_a = generate_3D_path_meshes_2D(path, p=(0, 0, 1))
        c_b, o_b, t_b = generate_3D_path_meshes_2D(path, p=(1, 0, 0))
        centers = np.concatenate([c_a, c_b], axis=0)
        triangles = np.concatenate([t_a, len(c_a) + t_b], axis=0)
        offsets = np.concatenate([o_a, o_b], axis=0)

    return centers, offsets, triangles