Issue: During animation work, Link Constraints set up through Fast-Ref disappear after Reload, or data is not properly restored.
User Experience: Restoration failure forces users to manually redo the work using Point Constraint and other methods, causing inconvenience.

Fast-Ref determines whether to restore data during Reload based on the following **'comparison algorithm'** to ensure data integrity.

Category	[Skip] Default Rigging State	[Restore] Fast-Ref Custom Work
Judgment Criteria	When the same Link already exists in both the Rig and Ani files	When the constraint does not exist in the Rig file but exists in the Ani file
Algorithm Behavior	Determined as ‘identical to source’ and ‘original rigging takes priority’ — ignored	Determined as 'user data' — recorded and restored separately
Design Intent	Optimized by skipping unnecessary constraint processing	Ensures that animation and constraint additions are automatically reflected in the Ani file

The issue experienced by the animator above is due to an edge case in the algorithm's **'decision logic'**.

Data misidentification: Since constraints already existed in both the rigging file and the animation file, the tool mistakenly assumed "this isn't something new the user created — it was already in the original rig" and **skipped it from restoration**.

The algorithm has been updated as follows to fully reflect the user's intent.

This method keeps the rigging file clean so the algorithm doesn't get confused when comparing the source and working files.

Description: Do not pre-apply Link Constraints to elements like weapons (Props) in the rigging source file.
Reason: If links already exist in the source, Fast-Ref may mistake the user's newly set links in the animation file as **"something that was already there"** and exclude them from restoration (Skip).
Recommendation: Leave weapons on the ground in a clean state, and have animators perform link operations through Fast-Ref in the animation scene — this ensures 100% reliable restoration.

This is a more advanced rigging approach that restructures the system to bypass the constraint restoration logic entirely.

Description: Instead of restoring constraints, control the connections through the controller's **custom Attributes (e.g., Switch 0/1)** or specific **drives (such as Position X values)**.
Reason: Since this approach does not create new constraints in the animation scene, there are no elements that need restoration, eliminating the risk of data loss at its source.
Note: This is also a recommended approach in standard rigging at major studios using Maya, etc., but implementing it requires collaboration with a dedicated **Rigger (Rigging TD)** within the team.