Rotation of an object around a fixed point

Hi Florent,

I recommend using a dial (see attached).

I (very roughly) cut out the lever in Photoshop, duplicated it and rotated the duplicated piece 180 degrees. I made the duplicated piece 95% transparent, just so you could see it (for your actual application, you'll want to make the duplicated piece 100% transparent). I merged the visible and nearly invisible lever into one object and saved that as a PNG. I imported the PNG into Storyline and converted the lever into a dial. I adjusted the dial start and end points to span 80 degrees. Lastly, I cut a small piece of the base of the device to overlay the rotation point (otherwise, even though it was visible, the full base graphic blocked the ability for the user to drag the lever).

It's very rough but I think you'll get the idea when you try it out. 

How about something like this (see attached)?

I added some instructions and changed the end value on the Design tab of the dial to 8 (change this to however many positions you would like the lever to have). Next, I displayed the current lever position on the slide. Then I added a button that shows a layer when clicked. The layer's properties are set so that the user cannot access the lever once they click Submit.

Note that the lever position is tracked in Storyline automatically by the dial variable created when the dial is created. I renamed this variable to Lever_Position to make it more obvious.