Apologies if this was posted in the wrong forum. I've managed to fix my problem by separating the xyz positions, connecting the y to the position of the slider and multiplying it by 2. Not sure I fully understand what I've done but it seems to work!

Hello All, I'm just discovering the wonder of expressions and although I'm finding it quite complicated I'm making some headway. However I've come up against a problem which I'm sure is simple but I'm having problems with. I am trying to animate a blinking eye so that when the eye lid closes the the...