Error: unreal engine collision not working

What's Causing This Error

Collision issues in Unreal Engine can stem from a variety of sources, including:

• Incorrect Collision Settings: The object may not have the correct collision preset or lacks a collision mesh. In some cases, the collision complexity setting might be inappropriate for how the object is used in the game.
• Physics Asset Problems: For skeletal meshes, an improperly configured Physics Asset (PhAT) can cause collisions to behave unexpectedly.
• Overlap Events Not Enabled: If you're expecting overlap events and they're not occurring, it could be because overlap events are disabled on the collider or the object is set to ignore the collision channel that triggers the event.
• Scale Issues: Non-uniform scaling or extreme scales can cause collision detection problems, as Unreal Engine's physics engine may not handle them correctly.
• Layer/Channel Misconfiguration: Unreal Engine uses layers or channels to determine which objects should collide with which others. If these are misconfigured, expected collisions won't occur.
• Movable vs. Static: A static object will not react physically to other objects, whereas a movable one will. If your object is set to static when it should be movable, this could be the issue.
• World Settings: Sometimes, global collision settings or project settings might override local settings, causing inconsistencies.

Solution - Here's How To Resolve It

To resolve collision issues in Unreal Engine, follow these steps:

1. Check Collision Presets: Verify that the collision presets are appropriate for the object's role in the game, such as 'BlockAll', 'OverlapAll', etc.

2. Inspect Collision Mesh: Ensure the object has a proper collision mesh. Use simple collision shapes where possible for performance reasons. Check the collision complexity and consider using "Use Complex Collision As Simple" if necessary.

3. Review Physics Asset: For skeletal meshes, open the Physics Asset Tool (PhAT) and make sure all bones that require collision have collision bodies attached and properly configured.

4. Enable Overlap Events: If overlaps are not triggering, ensure that 'Generate Overlap Events' is enabled in the object's collision settings.

5. Normalize Scale: Make sure the object doesn't have non-uniform scaling applied, as this can affect collision detection. Aim for uniform scaling factors.

6. Configure Layers/Channels: Go to Project Settings -> Collision to ensure that the collision channels are set up correctly so that the objects are interacting with the intended channels.

7. Adjust Movable/Static Setting: Change the object's mobility settings to 'Movable' if it needs to react to physics, or adjust other objects accordingly if there's a mismatch.

8. Global Settings: Look into the World Settings and ensure that the global collision settings match your expectations for the scene.

9. Rebuild Physics Data: In the case of persistent collision issues, try rebuilding the physics data within the engine.

10. Debugging Tools: Utilize the collision visualization tools (e.g., Show Collision) and the log outputs during gameplay to diagnose what's happening when collisions occur or fail to occur.

By carefully reviewing each of these areas, you should be able to identify and fix the collision issues in your Unreal Engine project.