SP_Floater is a LightWave Item Motion Modifier, created to make an object stay on top of an animated mesh, like a boat on water.
It can also be used to constrain an object to the Y-plane on any other kind of mesh, like making a car follow the shape of a landscape.
SP_Floater basically works by constraining a objects Y-position to the meshpoint it's closest to.
It's therefore important to use a higher mesh-density or more subdivision if you need smoother motion.
The items rotation is calculated according to the 'water's shape and can be faded on or off by an envelope,
the constrained Y-position can also be faded in the same way; So you can blend between keyframed values and SP_Floater-calculated values.
Turn off "Show Motion Paths" in LW's Preferences to avoid a slow performance, or else the plugin have to evaluate x times your frame range, for every frame!
Download SP_Floater here: SP_Floater[0.3b].zip