It is possible to create collisions (StaticMesh) for your Assets directly in Blender.

1. Select the mesh you want to add a collision to.
2. Go in Unreal Engine Panel > Object > Collisions.
3. Click "Create [Type] Collision from selection". (This will add created a child object that will be recognized as a collider by Unreal Engine.)

You can also directly convert an existing object to a collider.

1. Create a new mesh, it will be your collider shape.
   • An asset can contain multiple collider shapes but each collider must use a different object.
2. Select your collider Shape(s) and at the end select the owner object.
3. Go in Unreal Engine Panel > Object > Collisions.
4. Click "Convert to [Type]" (This will convert the selected object to collision except the last selected that the collision owner).
   • If you want to create a capsule, use 2 spheres in the same object.
     
   • If a "Not exported" child contains a collider, the collider will not be exported as the child.
   • If you change the name of the object that contains the collider, you will need to click on the Check potential errors button to update hierarchy name of all the colliders.

In the collisions settings you can chose if you want keep the original geometry and if you want use world space for specific colliders like the Box.

Here en example video: https://youtu.be/pfeWQfl3ACs

To be detected as collider in Unreal Engine the box must be perfect box. So when you create a box collider or convert a mesh as box the addon will create a minimal bounding box. For this the addon use two algorithms:

• Principal Component Analysis (PCA) oriented bounding box
  very fast and in the most of cases this algorithm give very good results.
  But you need to align your mesh with local axis or world axis when use world space or you will have this kind of result:
  

• Minimum Volume Bounding Box (MVBB) computation
  This algorithm always give the perfect bounding box but it is exponential slower with the number of faces...

  • 6 faces: <0MS
  • 56 faces: ~0.1MS
  • 4000 faces: 92 seconds...
  

Simple versus Complex Collision Reference about collision complexity flags and when to use them. In Unreal Engine, you have access to simple and complex collision shapes. Simple Collision are primitives like cubes, spheres, capsules, and convex hulls. Complex Collision is the trimesh of a given object. By default, Unreal Engine creates both simple and complex shapes, then, based on what the user wants (complex query versus simple query), the physics solver will use the corresponding shape for scene queries and collision tests.

In the Static Mesh Collision panel, you can find the settings for Collision Complexity in the Collision category.

For example, in the image below the chair on the left has simple collision, and when the Pawn above it falls onto it, it will slide off the large angled surface that covers the seat. However; the chair on the right is using Use Complex Collision As Simple, and when the Pawn above it falls, it will land on the seat of the chair and stay there.

• UE Docs: FBX Collision
• UE Docs: Interchange Collision
• UE Docs: Simple versus Complex Collision
• For community support and discussions, join the discord BleuRaven Side Projects.

• Download: AssetsExample_Collisions