> An artificial Pivot of the first object can't be X,Y,Z
> max/min of the object selected ?
> So the scale will be possible to calculate

That's certainly one possibility - but it would have some side-effects. For example if you had a line, as your line scaled down it would shrink around its own midpoint which would in effect move it away from touching the curve, even if it started out touching the curve. I'm not really sure that would always be the expected result - the problem is that you may need to control the origin of the scaling to get what you want.

This is one area where having a pivot point available on each object can be helpful.

- Michael