Hi,

I put a driver on the "Hair Length" of a particle emitter and calculate the value using the position of a empty object. The driver works and the "Hair Length" value is updated correctly, but it has no effect on the emitter. Only if I try to change the "Hair Length" value by hand, then the value snaps back to the calculated and the length of the hair also changes in view port, but in an animation this doesn't work automatically. Can someone help me with this issue?

Best regards,
_patrice_