Trail Controller | Unreal Engine 4.27 Documentation

The Trail Controller can be used to affect a series of bones in a hierarchy.

Property	Description
Trail
Trail Bone	Reference to the active bone in the hierarchy to modify.
Chain Length	Number of bones above the active one in the hierarcy to modify. Chain Length should be at least 2.
Chain Bone Axis	Axis of the Bones to point along trail.
Invert Chain Bone Axis	Whether or not to invert the direction specified in Chain Bone Axis.
Trail Relaxation Speed	How quickly we "relax" the bones to their animated positions. Time 0 will map to top root joint, time 1 will map to the bottom joint.
Limit
Limit Stretch	Limit the amount that a bone can stretch from its ref-pose length.
Stretch Limit	If Limit Stretch is true, this indicates how long a bone can stretch beyond its length in the ref-pose.
Velocity
Fake Velocity	The "fake" velocity applied to bones.
Actor Space Fake Vel	If "fake" velocity should be applied in Actor or World Space.
Base Joint	Base Joint to calculate velocity from. If none, it will use Component's World Transform.

Pin	Description
Input Pins
Component Pose	The incoming pose.
Alpha	The current strength of the control.

Trail Controller nodes are also affected by the LOD Threshold system introduced in 4.11. You can find the setting for this in the Details Panel for the Trail Controller node.

Property	Description
LOD Threshold	This is the max Level of Detail (LOD) that this node is permitted to run on. For example: if you have LOD Threshold set to 2, it will run until LOD 2, but disable itself once the component's LOD becomes 3.