Software Engineer - Simulation

FortyFive; Mountain View (CA); On-site; USD 100,000 - 130,000; Full time

Job summary

FortyFive is seeking a Simulation Engineer in Mountain View, California to build and scale physics simulation infrastructure. The role involves developing sim-to-real transfer pipelines and creating training environments for robotic systems. The ideal candidate has 3-5 years of experience in physics simulation or robotics, proficiency in relevant simulation tools like MuJoCo and PyBullet, and strong Python coding skills. Join our innovative team and contribute to revolutionizing AI in robotics.

Qualifications

• 3-5 years of experience with physics simulation or robotics software.
• Proficiency with simulation engines like MuJoCo, PyBullet, or Isaac Lab.
• Strong Python skills; familiarity with C++ for performance-critical code.

Responsibilities

• Build and maintain simulation environments using MuJoCo, PyBullet, and Isaac Lab.
• Develop sim-to-real transfer pipelines and domain randomization systems.
• Create scalable infrastructure for parallel simulation execution.

Skills

Physics simulation experience

Robotics software proficiency

Python programming skills

C++ familiarity

Understanding of robot dynamics

Tools

MuJoCo

PyBullet

Isaac Lab

Job description

Join Us in Building the Future of Physical AI

We build the simulation infrastructure for physical AI. We develop GenAI-powered tools that enable robotics teams to create unlimited, diverse training data and realistic evaluation environments. Our team spun out of MIT CSAIL, where we pioneered techniques that trained robots using only synthetic data. We're helping robotics companies transition to AI-native development workflows.

We're a lean team of researchers and engineers from DeepMind, OpenAI, FAIR, and top universities including MIT, Berkeley, Caltech, Harvard, and Yale. We've published best papers at top robotics conferences, won International Olympiad medals, and built core systems at leading AI labs. We believe in building complex systems that bring simplicity to our customers.

Global Team: We operate across US and China time zones. We value people who communicate proactively, document thoroughly, and take ownership of smooth handoffs across teams.

What to Expect

We're looking for a Simulation Engineer to build and scale our physics simulation infrastructure. You'll work on sim-to-real transfer, domain randomization, and creating training environments that enable robots to learn in simulation and perform in the real world.

What You'll Do

• Build and maintain simulation environments using MuJoCo, PyBullet, and Isaac Lab
• Develop sim-to-real transfer pipelines and domain randomization systems
• Create scalable infrastructure for parallel simulation execution
• Design RL training environments with realistic physics and diverse scenarios
• Collaborate with ML researchers on environment design for policy learning

What You'll Bring

• 3-5 years of experience with physics simulation or robotics software
• Proficiency with MuJoCo, PyBullet, Isaac Lab/Sim, or similar engines
• Strong Python skills; familiarity with C++ for performance-critical code
• Experience with reinforcement learning training pipelines
• Understanding of robot dynamics, kinematics, and control

Nice to Have

• Experience with sim-to-real transfer in deployed robotics systems
• Background in domain randomization and synthetic data generation
• Familiarity with GPU-accelerated simulation (Isaac Gym, Brax)
• Publications or projects in robot learning

We believe diverse teams build better products. Even if you don't meet every requirement listed, we encourage you to apply if you're excited about this role and our mission.