Any spline-based IGameObject can be converted to an IGameSpline object. This object is a container for the actual spline data, represented as one or multiple IGameSpline3D objects, depending on how many splines the original 3ds Max spline consisted of.

The knot and tangent data is stored within the IGameSpline3d object. Along with basic knot data, IGameSpline3D also stores the animation of any knot or tangent handle.

The diagram below shows the relationship of the IGameSpline container object to the IGameSpline3D objects it contains.

Splines are also used in conjunction with constraints for path-based animation, so they can be exported as part of the constraint data.