Physics collision issues after 40.00 update - objects tunneling through walls

Summary

After the 40.00 UEFN update, physics behavior appears to be inconsistent. In some cases, collision detection fails entirely, causing fast-moving objects to pass through solid geometry.

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Unreal Editor for Fortnite

What Type of Bug are you experiencing?

Assets

Steps to Reproduce

  • Open a UEFN project with physics-enabled objects
  • Use a small, fast-moving object (e.g. a golf ball 20cm~)
  • Apply a strong impulse or high velocity to the object
  • Aim the object toward a static mesh wall or collision surface
  • Repeat multiple times with high speed

Expected Result

The object should always correctly collide with walls and bounce or stop based on physics settings.

Observed Result

At high speeds, the object intermittently ignores collisions and passes through walls (tunneling effect), making gameplay unreliable.

Platform(s)

All

Island Code

8144-9733-4847

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Video

Quick update: it looks like this issue only occurs on static meshes where Collision Complexity is set to “Use Complex Collision As Simple”


The red mesh is using Complex Collision as Simple, while the green mesh is using Simple Collision

FORT-1076778 has been added to our ‘To Do’ list. Someone’s been assigned this task.