Implementation:Google deepmind Mujoco MJWarp Ray

Knowledge Sources	Google_deepmind_Mujoco MJWarp Documentation
Domains	Physics_Simulation, GPU_Computing, NVIDIA_Warp
Last Updated	2026-02-15 04:00 GMT

Overview

MJWarp Ray implements GPU-accelerated ray casting against all MuJoCo geometry types including meshes with BVH acceleration.

Description

This module provides ray intersection testing for all supported geometry types: plane, sphere, capsule, ellipsoid, cylinder, box, height field, and mesh. It includes both individual ray-geometry functions and batch ray-casting kernels that test rays against all scene geometries. The module supports BVH-accelerated mesh and flex ray queries, geom group and body exclusion filtering, and both closest-hit and any-hit query modes. Ray results include hit distance and surface normal at the intersection point.

Usage

Used by the sensor system for rangefinder sensors, by the renderer for ray-traced rendering, and by the SDF collision module for mesh-based signed distance evaluation. The ray and rays functions are the primary batch entry points.

Code Reference

Source Location

• Repository: Google_deepmind_Mujoco
• File: mjx/mujoco/mjx/third_party/mujoco_warp/_src/ray.py
• Lines: 1-1292

Key Functions

# Batch ray-casting entry points
def ray(...)   # Single ray against all geoms
def rays(...)  # Multiple rays against all geoms

# Per-geometry ray intersection
def ray_plane(pos, mat, size, pnt, vec) -> Tuple[float, wp.vec3]
def ray_sphere(pos, dist_sqr, pnt, vec) -> Tuple[float, wp.vec3]
def ray_capsule(pos, mat, size, pnt, vec) -> Tuple[float, wp.vec3]
def ray_ellipsoid(pos, mat, size, pnt, vec) -> Tuple[float, wp.vec3]
def ray_cylinder(pos, mat, size, pnt, vec) -> Tuple[float, wp.vec3]
def ray_box(pos, mat, size, pnt, vec) -> Tuple[float, vec6, wp.vec3]
def ray_hfield(...)
def ray_mesh(...)

# BVH-accelerated ray queries
def ray_mesh_with_bvh(...)
def ray_mesh_with_bvh_anyhit(...)
def ray_flex_with_bvh(...)

# Generic ray dispatcher
def ray_geom(pos, mat, size, pnt, vec, geomtype) -> Tuple[float, wp.vec3]

# Utility
def _ray_map(pos, mat, pnt, vec) -> Tuple[wp.vec3, wp.vec3]
def _ray_eliminate(...) -> bool

Import

from mujoco.mjx.third_party.mujoco_warp._src.ray import ray
from mujoco.mjx.third_party.mujoco_warp._src.ray import rays
from mujoco.mjx.third_party.mujoco_warp._src.ray import ray_mesh_with_bvh

I/O Contract

Inputs

Name	Type	Required	Description
m	Model	Yes	Warp model with geometry definitions and mesh data
d	Data	Yes	Warp simulation data with geom transforms
pnt	wp.vec3	Yes	Ray origin point
vec	wp.vec3	Yes	Ray direction vector
geomgroup	vec6	No	Geometry group filter flags
bodyexclude	int	No	Body ID to exclude from ray testing

Outputs

Name	Type	Description
dist	float	Distance to nearest intersection (-1 if no hit)
geomid	int	ID of the intersected geometry
normal	wp.vec3	Surface normal at intersection point

Related Pages

• Environment:Google_deepmind_Mujoco_MJX_Warp_CUDA_Environment