I am so kid in PI, but I am trying harder hehehehehe… the link below has 2 emitters… one from a flame i got here around and yours sperm that i changed just the shape… I am trying to do the sperm like the flame (i saw the flame has some other images, generating the animation)… the emitter by itself move the tail, so I can make a background moving from the left to right and show the ‘move’ of the sperm. And I will control the sperm just a little to front and back and much more in up and down in the scene…