Which physics engine should Gazebo use by default for real‑time simulation?
Goal: Identify the physics engine that should be set as Gazebo’s default so that typical simulations maintain a real‑time factor (RTF) of at least 1.0 without sacrificing numerical stability in multi‑body contact scenarios. Constraint: RTF measurements can be inflated by GUI rendering, making headless execution preferable for isolating physics bottlenecks, a