Changing the size of prims without moving them

I would like to be able to resize a prim using llSetScale() without the prim moving it's position relative to the ground.

For example a candle burning down.

When you use llSetScale() the prim position is taken from the centre of the prim so objects begin to float above surfaces as they shrink. Of course llSetPosition() could be used but this will be jerky.

What I'm after is a command or section of code that will smoothly lower the height of the prim without making it appear to float as it shrinks.

Is there infact a smooth way of doing this?

I considered using changing textures with alphas but again this does not seem an elegant solution.

I have never seen this in SL before to my knowledge.

Just to clarify... you DO want the prim to move when you shrink it in that case, because otherwise it looks like it is "melting from both ends". When you just use llSetScale, the prim does not move (its center) in relation to the ground.

Use llSetPrimitiveParams and set both PRIM_SIZE and PRIM_POSITION at the same time. That will prevent the "jerky" resizing in your situation.

This thread contains a script to stretch a prim from one end only by moving the center:

/54/81/189490/1.html#post1544238

The trick to use here is to cut the prim in half. So that its center point "moves" to one end of it.

This, of course, implies that you will only be able to use half of the prims maximum size.

I would suggest the same. A half a prim (Either cut 50% or using the sphere trick) with its center at the bottom would be the best way to ensure that it would shrink without having to be repositioned.