Motionbuilder Tutorial - 18: Spline Ik Online

: While MotionBuilder generates a default curve, you can also use a custom 3D Curve from the Elements folder of the Asset Browser for more specific pathing.

In MotionBuilder Tutorial - 18: Spline IK , you will learn how to use to animate flexible, multi-joint structures like tails, tentacles, and ropes . This specialized constraint aligns a skeleton joint chain along a curve, providing a smoother and more predictable way to achieve complex, aesthetically pleasing shapes than traditional FK or IK rigs. Core Workflow for Spline IK

: For complex characters, these controls can be added to a Character Extension (like a "Tail" extension) to ensure they are properly recognized and baked with the rest of the control rig. Best Use Cases Motionbuilder Tutorial - 18: Spline IK

Enable and click Snap to activate the constraint and bind the bones to the curve. Advanced Control Features

To set up a functional Spline IK system, follow these primary steps as detailed by Autodesk Help : : While MotionBuilder generates a default curve, you

: Ensure your joint chain is exactly perpendicular to the Y-axis ; otherwise, the constraint cannot be initialized. Apply the Constraint : Select the bones in your scene.

Under the tab, enter a value for the Number of control nodes . MotionBuilder will automatically create evenly spaced nodes along the skeleton chain. Core Workflow for Spline IK : For complex

: Ideal for any appendage that needs to deform in a serpent-like or "gooey" manner, which standard bipedal rigs can't handle.