What is the difference between ref ID and base ID in Skyrim?

Solution 1:

I found a Steam Forum post the explains the difference and has an example:

• BaseID is the ID of the default entry in the editor. If you place an item via its BaseID, you will always get the default, unmodified item.
• RefID is the ID that is given to each and every object in the world. For instance, If you have 2 Jarl Balgruufs, they share same BaseID, but have 2 different RefID. Just like every floor and wall tiles, etc.

Basically, the Base ID will always be the same for every object. The Ref ID depends on what instance it is in the world and is unique for each object. In the example above, the Ref ID could be used to distinguish the difference between two Jarl Balgruufs.

Solution 2:

The BaseID is the identifier for each "object". Be it actor, items, statics. It's always the same and unchanging. BaseID designate the dormant version of each objects, a blueprint so to speak.

The RefID on the other hand is an identifier assigned to each object once they get into the world.

For example, you can have a set of different NPC named "Guard". You want to populate an area and spawn 20 of them through placeatme or similar. They will each have an unique RefID, but some will share the same BaseID. The important element is that quests refers to other NPC and objects by their RefID, and thus you cannot just spawn a clone of a NPC and call it done.

This is how Skyrim generates dungeons. They have pools of blueprints and then spawn and level different actors when you enter the place.