Simulation Engineer / Robotics

Job Title: Simulation Engineer / Robotics Duration: 12 Months Location: Onsite in New York, NY or Menlo Park CA Physics simulation engineer with 5+ years of experience in contact physics, rigid-body simulation and differentiable/physics-based reward modeling for machine learning. This role owns a physics-based motion reward used to post-train generative video models via reinforcement learning: improving the dynamic and contact terms of the reward signal, optimizing it to run efficiently inside a large-scale RL training loop rather than as an offline filter, and extending it from single-body physical plausibility to human-object and human-scene interaction using 3D mesh representations. Required skills: R igid-body/contact simulation (MuJoCo, Isaac, Bullet or equivalent) * 3D human pose and motion representations (SMPL-family) Python/PyTorch with profiling and optimization of compute-heavy pipelines RL reward design and post-training of large generative models numerical methods and solver stability Education : MS or PhD in robotics, computer graphics, mechanical engineering, computer science or a related field, or equivalent industry experience in physics simulation. Preferred : Publications or open-source contributions in physics-grounded generative modeling, human motion generation, or differentiable simulation Experience with generative video or diffusion models Experience making simulation workloads run efficiently at scale (batching, GPU acceleration, distributed training) Experience validating simulated physical quantities against real-world or human-judged ground truth #J-18808-Ljbffr Spectraforce Technologies, Inc.