--- title: 'Simulation Engineer - Physics Modeling at 1X' canonical: 'https://feeny.ai/job/simulation-engineer-physics-modeling-1x-san-carlos-8kyxp89kyfc3' type: 'job' last_seen: '2026-09-20' --- # Simulation Engineer - Physics Modeling at 1X - **Company:** [1X](https://feeny.ai/companies/1x) - **Location:** San Carlos, CA - **Compensation:** $200k–$280k - **Employment:** full-time - **Work type:** onsite - **Posted:** 2026-06-17 - **Last confirmed live:** 2026-09-20 - **Apply:** https://jobs.ashbyhq.com/1x/bd7452e9-1f5a-4e49-b468-2ad98c20e2c3/application **Skills:** Python, C++, MuJoCo, PyBullet, Isaac Sim, OpenGL, Physics simulation, Rendering pipelines, Testing practices, Extrinsic and intrinsic calibration algorithms, Domain randomization, Procedural environment generation, Differentiable simulation, GPU-accelerated physics, Warp, JAX-based simulators, Legged locomotion, Dexterous manipulation > Build and maintain physically realistic simulation environments and infrastructure to accelerate robot learning for NEO. Narrow the sim-to-real gap, scale synthetic data production, and enable virtual hardware prototyping. ## Job description ## About 1X We're building humanoid robots that work in home - doing the chores, handling the tasks, and giving people their time back. Simple, but it's not. To do this right, we have to solve robotics, AI, manufacturing - at the same time, at scale, in a form factor that has to be safe enough to live with your family. If you're inspired by this, you'll thrive here. We've been at this since 2014 and we're at the point where the hard problems are behind us and the hard work is in front of us. NEO is our flagship - a home robot designed to move, learn, and operate in the real world alongside real people. We're not demoing it - we're shipping it. We're excited to meet you, if this excites you. If you've spent your career working on problems that matter and want to see them actually reach the world - this is that moment. We're scaling, we're hiring with intention, and we need people who want to build something that will genuinely change how humans spend their time - safely creating abundance for all. ## About the Team The Simulation team builds the virtual environments and infrastructure that let 1X's AI team iterate on robot learning without being bottlenecked by real hardware. We construct physically realistic simulation worlds for NEO, scale synthetic data production, close the sim-to-real gap, and prototype new hardware virtually before it's manufactured. Our work is a force multiplier for every research and development team at 1X: the faster and more faithfully we can simulate NEO's world, the faster the whole company learns. ## Your Charter Close the gap between how NEO behaves in simulation and how it behaves in the world. You will make the simulator physically accurate enough that results earned in simulation hold up on hardware, building and validating the dynamics, material, and sensor models that decide whether a simulated result means anything. Every team that trains or evaluates against simulation is betting on the fidelity you deliver. ## Key Outcomes - Physical Accuracy: Improve contact dynamics, articulated body models, and actuator and transmission fidelity, driven by system identification data from real hardware and kept current as hardware changes. - Compliant and Deformable Bodies: Model soft contact and structural compliance where rigid-body assumptions break down, so grasping and contact-rich behavior transfers instead of only working in simulation. - Sensing Realism: Model the sensing path as it actually behaves - noise, bias, dropout, latency, and sample timing - so a policy sees in simulation what it will see on the robot. - Measuring the Gap: Establish the benchmarks and real-robot comparisons that quantify sim-to-real error, so fidelity work is driven by evidence rather than intuition. - Randomize or Model: Decide which discrepancies to model faithfully and which to randomize over, with ranges grounded in the spread measured across the real fleet. - Determinism and Reproducibility: Make runs reproducible given the same inputs, so a regression is a real regression and any failure can be replayed and debugged. - Throughput and Environments: Optimize physics and rendering, and deliver the diverse environments and synthetic data pipelines that feed policy training and evaluation. ## Key Competencies - Physics Simulation Depth: Knows what makes a simulator physically accurate and computationally tractable, and how to tune contact dynamics and articulated body models for robot learning. - Sim-to-Real Judgment: Knows which differences between simulation and reality actually matter for policy transfer, and which can be absorbed by randomization. - Grounded in Real Data: Validates fidelity against measurements from real robots rather than trusting a simulation that looks right. - Fleet Thinking: Treats unit-to-unit variation across real robots as something to measure and model, not average away, so simulation reflects the fleet rather than one nominal unit. - Performance Engineering: Optimizes physics and rendering pipelines for throughput, and reasons explicitly about the tradeoff between fidelity and speed. - Rigorous Infrastructure: Writes tested, maintainable simulation code other teams depend on, treating determinism and correctness of the stack as first-class concerns. - Technical Direction: Sets the approach for a problem area, defends tradeoffs across fidelity, throughput, and effort, and partners with the teams that depend on simulation. ## Minimum Requirements - Strong programming in Python, C++, or similar languages, with experience building environments or benchmarks using robotics simulators (MuJoCo, PyBullet, Isaac Sim, or equivalent) - Demonstrated experience improving simulation fidelity and closing the sim-to-real gap for behavior that had to work on physical hardware - Experience modeling sensors and their failure modes in simulation, including noise, bias, latency, and dropout - Experience improving the performance of physics simulators or rendering pipelines - Strong testing practices for simulation stacks used in robot learning, including tests that verify physical correctness and catch regressions - 5+ years of relevant industry experience, or an advanced degree plus equivalent hands-on experience ## Preferred Skills - Experience with system identification on real hardware, and with turning measured parameters into simulation models - Experience with procedural environment generation or other techniques for scaling diverse simulation data production - Familiarity with differentiable simulation, learned or neural simulators, or GPU-accelerated physics such as Warp or JAX-based frameworks - Background in legged locomotion, dexterous manipulation, or contact-rich and deformable-body simulation ## Compensation - Salary Range: $200,000 - $300,000 + Equity ## Benefits - Comprehensive medical, dental, and vision coverage - Generous paid time off, company holidays, and parental leave - 401(k) plan with company match (100% on the first 3% of contributions, 50% on the next 2%) - Flexible Spending Accounts (FSA) and Health Savings Accounts (HSA) options - Commuter benefits (transit and parking) - Short-term and long-term disability, and life insurance - Employee Assistance Program (EAP) for mental health, financial, and personal support - Onsite snacks and catered lunches ## Equal Opportunity Employer 1X is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, gender, gender identity or expression, sexual orientation, national origin, ancestry, citizenship, age, marital status, medical condition, genetic information, disability, military or veteran status, justice system impact, or any other characteristic protected under applicable federal, state, or local law. ## About 1X ## Company Overview - **One-liner**: 1X develops general-purpose humanoid robots for home and industrial environments, combining AI and hardware to automate everyday tasks. - **Entity Type**: Private (Series B funding stage) - **Headquarters**: Palo Alto, California, United States - **Founded**: 2015 - **Founders**: Bernt Øyvind Børnich ## Core Business - **Primary industry**: Robotics Engineering / Artificial Intelligence - **Target customers**: B2C (home consumers via NEO) and B2B/Enterprise (industrial tasks via EVE) - **Mission**: Build a truly abundant society through general-purpose robots capable of performing any kind of work autonomously, allowing humans to focus on what they love. ## Products & Services - **NEO**: A friendly home humanoid robot designed to integrate seamlessly into daily life and handle chores. Currently in early access after the NEO Beta (2024) and NEO Gamma (2025) iterations. [1x.tech](https://www.1x.tech/about) - **EVE**: A wheeled industrial humanoid deployed in factories worldwide for autonomous industrial tasks. [1x.tech](https://www.1x.tech/about) - **Revo1**: A high-torque-to-weight drive servo motor inspired by human tendon actuation, used in 1X robots. [1x.tech](https://www.1x.tech/about) - **1X World Model**: A physics-grounded video model that enables NEO to learn autonomously from text or voice commands. [linkedin.com](https://www.linkedin.com/company/1x-technologies) ## Market Standing - **Valuation**: Not publicly disclosed - **Key Metric**: Total funding of $169M as of mid-2026, with a $100M Series B led by EQT Ventures in January 2024. [linkedin.com](https://www.linkedin.com/company/1x-technologies) - **Notable Investors/Partners**: EQT Ventures (lead), plus other investors in secondary rounds. Acquired Kind Humanoid in January 2025. [linkedin.com](https://www.linkedin.com/company/1x-technologies) - **Growth Signals**: - Headcount grew 121.2% YoY to 394 employees. [linkedin.com](https://www.linkedin.com/company/1x-technologies) - Full-scale production of NEO began in Hayward, CA, with capacity to build 10,000 units per year. [linkedin.com](https://www.linkedin.com/company/1x-technologies) - New Palo Alto HQ consolidated teams from Sunnyvale and Moss, Norway. [linkedin.com](https://www.linkedin.com/company/1x-technologies) - Appointed Mohi Khansari as Head of Robot Learning (January 2026) and Vikram Kothari as VP of Operations (August 2025). [linkedin.com](https://www.linkedin.com/company/1x-technologies) ## Competitive Advantages - **Vertical integration**: Owns manufacturing in Hayward (U.S.) and Moss (Norway), controlling the full production stack. - **Proprietary hardware**: Revo1 servo motor offers world-leading torque-to-weight ratio, enabling flexible, low-gear-ratio robotics. - **AI-first approach**: The 1X World Model allows robots to learn physical tasks via simulation and self-supervised video prediction, reducing need for manual programming. - **Early home deployment**: NEO is one of the first humanoid robots entering private homes, giving 1X real-world data and feedback loops. ## Strategic Focus - Scaling NEO production and expanding early access to more households across the U.S. - Enhancing AI capabilities through the World Model and reinforcement learning (e.g., Redwood mobility controller). - Building a robust supply chain and service network for home robots. - Continuing enterprise deployments of EVE while shifting emphasis to the consumer market. ## Why Work Here - **Culture**: Fast-paced, mission-driven environment focused on building humanoid robots that coexist with humans. Strong emphasis on AI, hardware, and real-world impact. - **Work model**: Likely on-site for hardware and AI roles (multiple offices in Palo Alto, San Carlos, Sunnyvale, Hayward, and Moss). Some software roles may offer flexibility. - **Notable perks**: Opportunity to work on cutting-edge robotics and AI, contribute to a product (NEO) that is already entering homes, and be part of a rapidly scaling company with strong funding. - **Engineering culture**: High concentration of talent from Tesla, Apple, Google, and SpaceX. Active research in biomechanics, reinforcement learning, and simulation. [linkedin.com](https://www.linkedin.com/company/1x-technologies) - **Open roles**: 65+ positions listed on the careers page across AI, hardware, software, operations, and manufacturing. [1x.tech](https://www.1x.tech/careers) ## Sources 1. [1x.tech](https://www.1x.tech/about) 2. [1x.tech](https://www.1x.tech/careers) 3. [linkedin.com](https://www.linkedin.com/company/1x-technologies) ## Other roles at 1X - [Internship - CNC Machine Park](https://feeny.ai/job/internship-cnc-machine-park-1x-hayward-bdkw3zkk5pa2) — Hayward, CA - [Production Supervisor - Body](https://feeny.ai/job/production-supervisor-body-1x-hayward-kasd33mpzjgt) — Hayward, CA - [Production Supervisor - Hands](https://feeny.ai/job/production-supervisor-hands-1x-san-carlos-nagxpxvb4bza) — San Carlos, CA - [Robot Assembly Technician](https://feeny.ai/job/robot-assembly-technician-1x-hayward-b4yt43a0s439) — Hayward, CA - [Robot Assembly Technician - Hands](https://feeny.ai/job/robot-assembly-technician-hands-1x-san-carlos-217s2y4txr3t) — San Carlos, CA - [Recruiting Coordinator](https://feeny.ai/job/recruiting-coordinator-1x-san-carlos-7syy9m0c2esv) — San Carlos, CA - [AI Researcher - Perception](https://feeny.ai/job/ai-researcher-perception-1x-san-carlos-ydyqjrthn02c) — San Carlos, CA - [Internship - Manufacturing Engineering](https://feeny.ai/job/internship-manufacturing-engineering-1x-san-carlos-w4x93jk7gwpw) — San Carlos, CA - [Motor Test Technician](https://feeny.ai/job/motor-test-technician-1x-san-carlos-zsyhcdhha6ew) — San Carlos, CA - [Operator - Data Collection (Swing Shift)](https://feeny.ai/job/operator-data-collection-swing-shift-1x-san-carlos-36y5yx97sgj2) — San Carlos, CA