Animation menu > Constraints > Attachment Constraint
The Attachment constraint is a Position constraint that attaches an object's position to a face on another object (the target object doesn't have to be a mesh, but must be able to convert itself to a mesh).
By keying different attachments over time, you can animate the position of an object over the irregular surface of another object, even if that surface is changing over time.
Vot jeshchio odna ssylochka (novyj script kak raz dlia tebia):
Follow Surface 1.1 3ds max 4.x
Here's a script to allow an object to follow the contours/etc. of another object. It's called 'Follow_Surface' and it will enable you to have an object follow a surface even if the surface is animated. You can also follow the surface with a time delay (like a buoy does when it's floating on water).
Written by Shawn Lewis.