Source code for concepts.math.cad.mesh_utils

#! /usr/bin/env python3
# -*- coding: utf-8 -*-
# File   : mesh_utils.py
# Author : Jiayuan Mao
# Email  : maojiayuan@gmail.com
# Date   : 08/1/2024
#
# This file is part of Project Concepts.
# Distributed under terms of the MIT license.

import open3d as o3d
import numpy as np

from typing import Optional, Tuple




def mesh_line_intersect(t_mesh: o3d.t.geometry.TriangleMesh, ray_origin: np.ndarray, ray_direction: np.ndarray) -> Optional[Tuple[np.ndarray, np.ndarray]]:
    """Intersects a ray with a mesh.

    Args:
        t_mesh: the mesh to intersect with.
        ray_origin: the origin of the ray.
        ray_direction: the direction of the ray.

    Returns:
        A tuple of (point, normal) if an intersection is found, None otherwise.
    """

    scene = o3d.t.geometry.RaycastingScene()
    scene.add_triangles(t_mesh)

    ray = o3d.core.Tensor.from_numpy(np.array(
        [[ray_origin[0], ray_origin[1], ray_origin[2], ray_direction[0], ray_direction[1], ray_direction[2]]],
        dtype=np.float32
    ))
    result = scene.cast_rays(ray)

    # no intersection.
    if result['geometry_ids'][0] == scene.INVALID_ID:
        return None

    inter_point = np.asarray(ray_origin) + np.asarray(ray_direction) * result['t_hit'][0].item()
    inter_normal = result['primitive_normals'][0].numpy()
    return inter_point, inter_normal