differt.rt.first_triangle_hit_by_ray

first_triangle_hit_by_ray(ray_origins, ray_directions, triangle_vertices, active_triangles=None, batch_size=512, **kwargs)

Return the first triangle hit by each ray.

This function should be used when allocating an array of size *batch num_triangles 3 (or bigger) is not possible, and you are only interested in getting the first triangle hit by the ray.

If two or more triangles are hit at the same distance, the one with the closest center to the ray origin is selected. Two triangles are considered to be hit at the same distance if their distances differ by less than 100 * eps, or ten times the epsilon keyword argument passed to ray_intersect_triangle.

Note

This function has a faster and more memory-efficient equivalent method: TriangleMesh.first_triangle_hit_by_ray, as long as smoothing is not required.

Parameters:

• ray_origins (Float[ArrayLike, '*#batch 3']) – Origin vertex.

• ray_directions (Float[ArrayLike, '*#batch 3']) – Ray direction. The ray end should be equal to ray_origins + ray_directions.

• triangle_vertices (Float[ArrayLike, '*#batch num_triangles 3 3']) – Triangle vertices.

• active_triangles (Bool[ArrayLike, '*#batch num_triangles'] | None) – Optional active triangle mask.

• batch_size (int | None) –

  The number of triangles to process in a single batch. This allows to make a trade-off between memory usage and performance.

  The batch size is automatically adjusted to be the minimum of the number of triangles and the specified batch size.

  If None, the batch size is set to the number of triangles.

• kwargs (Any) – Keyword arguments passed to ray_intersect_triangle.

Return type:

tuple[Int[Array, '*batch'], Float[Array, '*batch']]

Returns:

Index of and distance to the first triangle hit by each ray.

If no triangle is hit, the index is set to -1 and the distance is set to inf.