UE5 Animation Sample:
Custom Integration & Tuning
Level Design
QA Analysis
Kitbash
Engine: UE5.6
Mission Brief
This case study focuses on identifying and resolving critical physics performance bottlenecks in a racing game environment. By implementing a systematic stress-testing methodology and optimization strategy, the goal was to secure a stable Performance Budget for high-fidelity visual effects (VFX) without compromising gameplay stability.
Bug Report
Summary: CPU Physics simulation overhead exceeds 23ms when spawning 500 active rigidbodies.
Steps to Reproduce:
Step 1: Use the
PhysicsStressTest.csscript to initiate the testing environment.Step 2: Spawn 500 objects configured with Convex Mesh Colliders.
Step 3: Observe and record the
Physics.Simulateexecution time within the Unity Profiler.
Expected: Physics simulation should stay under 5ms to maintain 60 FPS.
Actual: CPU time reached 23.42ms, causing significant frame drops.
Recommendation: Replace Convex Mesh with Compound Box Colliders (Option 2).
Option 1: Convex Mesh Collider (Pre-Optimization)
This approach utilizes the model's original mesh with the Convex setting enabled. While it is quick to set up and provides a precise fit to the visual model, it imposes a heavy computational burden during high-density object interactions.
Test Performance: Generated approximately 219 Total Contacts, with physics memory usage reaching 31.6 MB.
Execution Overhead: CPU time per frame peaked at 23.42ms.
Result Analysis: This value significantly exceeds the 16.6ms (60 FPS) threshold. Attempting to implement VFX in this state would result in severe frame drops and stuttering.
Option 2: Simplified Box Colliders (Post-Optimization)
The complex mesh was decomposed into several primitive geometric shapes (Box Colliders) to form a Compound Collider.
Test Performance: Total contacts were reduced to 105, and physics memory usage dropped to 8.3 MB.
Execution Overhead: CPU time per frame was drastically optimized to 4.00ms.
Result Analysis: The optimized physics simulation now occupies only a small fraction of the frame budget. This successfully secures ample computational margin for high-quality visual effects, ensuring smooth performance across a wide range of hardware specifications.