You said in another thread that you were using this to make the holes in your golf game. But I'm curious...
Would it not be easier for you to draw a black circle on a sprite, align it to a terrain (with aligntovector), and check for sphere-to-sphere collisions between that and the ball?
If they collide, you can gradually move the ball towards the centre (X/Z axes) of the hole, then move it down the Y axis so it appears to drop into the hole.
That's how I'd do it anyway. Saves messing up your landscape geometry.
Would it not be easier for you to draw a black circle on a sprite, align it to a terrain (with aligntovector), and check for sphere-to-sphere collisions between that and the ball?
If they collide, you can gradually move the ball towards the centre (X/Z axes) of the hole, then move it down the Y axis so it appears to drop into the hole.
That's how I'd do it anyway. Saves messing up your landscape geometry.