Unreal Actors can have a collision components added to them, I’ll call them Colliders.
There are 3 shapes you can select Sphere, Box, Capsule, they share the same functionality so pick the one that best match what you are trying to do. What really matters is how well it matches to your object shape for better collision detection. And if you will use physics simulation, spheres will roll, capsules tip over, boxes are more stable kinda stuff.
Static Meshes can also have colliders but I’m focusing on the collider components for now.
When two colliders touch Unreal checks both colliders Object Type to determine how to react. The reaction can be Ignore, Block, Overlap.
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Ignore - Object will move through the collider, no events hit events will be triggered.
Block - The Object won’t be able to move through and a Event Hit will be triggered.
Overlap - The collider will be able move through the other collider it just hit. On entry Event Begin Overlap will be triggered and Event End Overlap when the instigator collider leaves.
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You can find the Object type of your collider in the Collision section of the Details tab.
When a collider hit something, it generates a Hit Event. This where you add logic to handle what happens next.
Overlap is useful for anything that revolves around being able to enter and leave a collider space. For example automatic doors, environment traps that reset.
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Overlap events only fire if BOTH colliders have Generate Overlap Events ticked on.
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TIP: Use Primitive Component variable type when you need to reference a collider you don’t know yet. Primitive Component type cover all 3 collider types. (Box, Sphere and Capsule)
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