If the local player is creating an object, then the function they use will determine whether or not other players can see and interact with that object. The most basic example that I can think of is the difference between these two functions.
spawn_sync_object()
and
spawn_non_sync_object()
The spawn_sync_object() function will spawn an object that will be synchronized between players. Inversely, if you use spawn_non_sync_object() then the object will NOT be synchronized between players. There are other functions that spawn specific objects, such as particles. If you aren't sure which function to use to summon your object, try giving spawn_sync_object() a try and passing the behaviors and meshes the object would normally have. For example,
spawn_sync_object(id_bhvGoomba, E_MODEL_GOOMBA, m.pos.x, m.pos.y + 200, m.pos.z, nil)
This function will spawn a goomba above the Mario that triggered it that ALL players can interact with, because it was spawned with spawn_sync_object().
I hope this answers you question. If you have any other questions, feel free to ask.
- SkyCaster09