AddOnNode

The add-on node system allows one NIF model to include the contents of another NIF model by reference. You can't specify arbitrary NIF files; rather, the game data defines a library of reusable NIFs.

In your ESP file, you can define an "AddOnNode" form, which consists of a 3D model and a unique numeric ID. Then, in any NIF file, you can create a BSValueNode. This is, functionally, just a local transform (i.e. offset from its parent node) and a value. In practice, however, the "value" specifies one of those unique numeric IDs. Skyrim will look up the appropriate AddOnNode form, load its NIF, and copy the contents of that add-on NIF to where the BSValueNode is.

Here are a few examples:

• Effects\CWFXCatapultProjectile.nif uses several add-on nodes with IDs 5, 6, 71, and 74.
  • The ID 5 is defined by [ADDN:0001CBB2]MPSFireBallSparkTrail.
  • The ID 6 is defined by [ADDN:0001CBB1]MPSFireBallSmokeTrail.
  • The ID 71 is defined by [ADDN:000E1532]MPSDragonFireWave.
  • The ID 74 is defined by [ADDN:000EE9ED]MPSFireBallSmokeTrailBig.

Each of these Add-on Node forms specifies a NIF file; so, a Civil War catapult projectile can include the 3D effects for sparks, smoke, flames, and smoke trails entirely by reference.

• Effects\AshPile01.nif uses a single add-on node with ID 61. That ID is defined by [ADDN:00E7556]MPSAshPile01, which seems to be purpose-built for this particular model.

AddOnNode Dialog

• ID: Unique identifier for this form.
• Addon Node Index: This is the index used for modeling purposes.
• Model: Name of the file for the effect or model. Click the Edit button to bring up the Model Data window.
• Sound: Sound that plays when AddOnNode is activated, such as when a small fire starts on a car when the car has been shot multiple times.
• Master Particle System Cap: This is currently not in use.