Learn the essential steps to configure collision for your 3D models in Unreal Engine, ensuring objects interact realistically within your game world.
Find your Static Mesh asset in the Content Browser and double-click it. This will open the dedicated Static Mesh Editor window.
In the Static Mesh Editor toolbar, click the Collision dropdown and select Simple Collision. Any existing simple collision shapes will appear as green wireframes around your mesh.
If no collision exists, go to the Collision menu at the top. Choose an appropriate shape to add, such as Add Box Simplified Collision, Add Sphere Simplified Collision, or Add Capsule Simplified Collision.
Select the green collision primitive in the viewport. Use the standard transform gizmos to Move (W), Rotate (E), and Scale (R) the shape to fit your mesh as accurately as possible.
In the Details panel on the right, scroll down to the Collision section. Use the Collision Presets dropdown to define how this object interacts with others (e.g., BlockAllDynamic, OverlapAll, or NoCollision).
Pro Tips for Effective Collision
Always use simple collision shapes (boxes, spheres, capsules) for game-play interactions. They are significantly more performant than using the mesh's actual geometry for collision.
For highly detailed but non-interactive objects, you can set Collision Complexity to Use Complex Collision As Simple. This is great for things like detailed environments but is expensive for dynamic objects.
In the main editor viewport, press Alt + C to toggle the visibility of collision primitives for all actors in your scene. This is invaluable for debugging.
For advanced interactions, go to Project Settings > Engine > Collision. Here you can create custom Object Channels and Trace Channels for fine-grained control over what collides with what.
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