Mesh/Component Interaction ?

Please correct my terms if I’m incorrect with any, But…
It’s my understanding that object/meshes i.e. Terrain, FBX or UE4 native meshes have three fundamental categories of interaction, along with the more detailed abilities of each of their categories.

  1. Collision Detection
  2. Hotspots or being within a defined coordinate range. ( Whatever UE4 calls it ? )
  3. Direct Blueprint or source code referencing. e.g. obj1->attr1 = obj2->attr1;

Am I missing any other general top level category of interaction?
I’m looking for the top level categories that anything can use to interact with anything else within UE4.

They don’t haft to be common across everything, but they do need to be general within their category.