I know I can control an objects pivot point using the insert key , what about expressions , like being able to keep a pivot point at a YMIN or YMAX. I have a box object attached to particles. As the length alters of my box I want the pivot to remain at something like the BBY min value is this possible ?

rob

haven't you just answer you question? If your box is growing using transform SOP just put $YMIN to pivoty field.

dam it … :roll: