The tySplineCache modifier extracts spline cache data loaded into a tyCache object, and converts it into editable splines.
Spline data exported from an Export Particles operator is stored in a mesh-based format. This modifier, when placed on a tyCache object that contains that data, will convert it into a format that 3ds Max can recognize as traditional, editable splines.
Linear/Smooth: the type of interpolation to apply to spline knots.
Steps: the number of interpolation steps to apply to splines.
Optimize: controls whether or not the step count will be optimized depending on the spline curvature.