What I think:
- Players will be able to grab objects
- Players will then be able to hold the object as they move with them
- Players will be able to drop the objects in the trigger volume
- The trigger volume will check if all objects required are there before opening the door
- The trigger volume will have a script component that checks this
Other Ideas:
- Maybe players will have to put objects in trigger volume in a specific order
- Maybe players will have to put some objects in trigger volume and leave some objects out
- Maybe players will have to look for the objects as they may be hidden