Rotation question

I know that when you set rotation of an object using llSetRot it pivots around the root prim, not the center of the item (as opposed to when you just edit it and spin it). Is there a way to change this?

add an invisable root prim to move center

Unfortunately that wont work for me. OK let me try to explain.

I'm building a contraption (fish-hook suspension rig for those who know what it is - for those who dont.. you dont want to *grin*), which is basically a block hanging from a pulley system. I need the lower pieces to rise up and down relatively smoothly and the whole thing to pivot around the upper pulley which needs to remain stationary. If I put the root prim in the block portion of the contraption I can use raise the entire piece and just reposition the upper wheel in small increments as the contraption rises. But then when I got to pivot the piece it teeters around the root prim - not the upper wheel. If I make the upper wheel the root prim then each of the other peices of the contraption has to rise seperately and the vertical movement gets all chunky jumpy. I'm trying to figure a work around.

How about just rotating/moving the whole linkset in world-coordinates? I.e. rotate the set AND move it. I don't know how smooth that would look for your specific application, but I've done that kind of thing a few times and it worked well for me.

Oh just thinking about that math makes me whimper - lol - but I'll bet you're right. Thank you!

Honestly, it's not difficult. The example, in the section of the wiki article http://wiki.secondlife.com/wiki/Rotation headed "Position of Object Rotated Around A Relative Point" (towards the end of the page) breaks it down step by step, and you can do it all using llSetPrimitiveParams to get a nice smooth effect.

Give it a try. it's really not hard to do.

Oh very cool thank you!!!