fixed-step-simulation

What problem does it solve?

Variable render frame time can cause inconsistent simulation results, incorrect physics integration, and gameplay that changes depending on performance.

Core Features & Use Cases

• Fixed-timestep ticking: Runs selected simulation systems in FixedStepSimulationSystemGroup so logic updates at a known rate (e.g., 30Hz/60Hz) regardless of render framerate.
• Correct time source usage: Uses SystemAPI.Time.DeltaTime inside the fixed-step group so the simulation consumes the fixed delta rather than the render delta.
• Deterministic gameplay & physics: Ensures physics integration and frame-rate-independent behavior for systems that must tick consistently, including deterministic replay and network prediction.

Quick Start

Use FixedStepSimulationSystemGroup with [UpdateInGroup(typeof(FixedStepSimulationSystemGroup))] and read SystemAPI.Time.DeltaTime inside the system to drive your simulation at the fixed timestep.