Simulation Engineer (C++)

# Simulation Engineer (C++)

Type: Full-time

Location: Remote-first, async-first, would be an advantage — based in Spain: immediate start or after the probation period.

Compensation: Competitive salary + founding-team equity

## The Role

You will own the simulation core — the physics engine, sensor simulation, and the bridge between C++ physics and the rest of the platform. This is not a feature team role. The simulation core *is* the product.

Your work includes:

• MuJoCo integration — deterministic mode (single-threaded, version-pinned, `-fno-fast-math`), configuration management for timestep/solver parameters across vehicle types
• Shared-memory IPC — out-of-process ring buffer bridging C++ physics to the platform layer
• ROS2 C++ bridge — native ROS2 integration so customers can use standard tooling (rviz2, rosbag, ros2 topic)
• Sensor simulation plugins — LiDAR ray-casting (Intel Embree), camera, IMU, GPS with physics-state projection annotations
• Open-source Nonlimi Core — your work ships under Apache 2.0

Over 12 months, you’ll extend to DART for articulated manipulators, multi-domain physics (UAV blade element momentum), and USD pipeline integration.

## Requirements

These are hard gates:

• C++ systems engineering, 4−7 years — performance-critical C++ where memory layout, cache behavior, and undefined behavior were first-class concerns
• Physics engine internals — MuJoCo, Bullet3, PhysX, DART, or Gazebo at the integration level — constraint solver configuration, determinism flags, collision shape management
• C++ shared-memory IPC — POSIX SHM, lock-free ring buffers, std::atomic with explicit acquire/release/seq_cst ordering
• Non-determinism debugging — you have found and fixed a case where physics state diverged across runs, across machines, or after a compiler upgrade

## Nice to Have

• MuJoCo C API directly (not just mujoco-py or dm_control wrappers)
• ROS2 C++ (`rclcpp`, DDS transport, composable nodes, lifecycle nodes)
• pybind11 or similar C++/Python binding experience
• Godot 4 or real-time scene graph experience (Unity, Unreal at the renderer level)
• Sim-to-real deployment — taken a policy from simulation to a physical robot

## What We Offer

• Competitive salary
• Full architectural ownership — Nonlimi Core is yours to design, build, and evolve
• Open-source impact — you’re building simulation infrastructure the robotics community will use
• Direct customer access — you’ll talk to autonomy startups and robotics labs directly

## How to Apply Send us an example that demonstrates relevant work that you are particularly proud of — a GitHub project, a PR to an open-source project, a Gazebo plugin, a physics engine integration.