I would be interested if it is possible to leave a trace after a ball moving along a complicated, curved line? It is simply to do it with a straight line - you just use a mask.
Thank you for clues,
Do you mean something like motion tween , Not ? ok then i hope i got your question, if you give the mc ball a name like ball and use a script to duplicate it from its last position and give the duplicated mc a alpha value from 25% it is just like a leaving a trial behind.