Distance Driver Not Working

Hi,

I have a distance driver set up on some controls that won’t work. Like in this video: https://www.youtube.com/watch?v=Rf3JBuSLRKU

I did it in his example project and it worked perfectly! I’m setting up a control object to toggle an objects visibility based off the distance between a control and the reference image.

However, it doesn’t seem to be working in my own project? I’ve attached my blend. Object MA is the object with the driver on it’s visibility.LK Pip Rig 04.blend (3.07 MB)

http://www.pasteall.org/blend/37220

Transform Space and Averaged Values work much better for some reason.