hi guys,long time no see .

I am trying to get some fluid erosion effects. I use a lot of boxes interacting with fluid. And at each frame I get the fluid speed near each box, transfer it to the center point of the box, then the box with max speed should be deleted. So the effect like the boxes are disappeared frame by frame.

Now the problem comes, I can not keep the state of the boxes in last frame. It always eroded from the first state. What I wish is the boxes are eroded little by little. So how can I keep the shape interact with fluid from frame to frame.

Hope some nice guy can help me. the file is attached.

probably a better way to do this but i've got a killer headache right now..

stored your points in to a group after collecting them in a source pop. then transferred them back over and deleted the additive group.

hth,
dave

thanks very much for your kindness. I will see it soon