# Using a driver to control two shapekeys but triggering the second shapekey when the bone hits a certain value

I'm trying to use a single bone to control a blink on a cartoony character it's normally pretty simple but for this I need the eyelids to disappear at a certain point like when the eyelids are completely wide open.

Right now I have a bone simply driving the shapekey value of the blink from 0 - 1 but I need it to trigger a second shapekey when the bone hits a value of 0.8 or 0.9 so the second shapekey can hide the eyelids by shrinking them down. Not sure if there's a way use the expression box in the driver panel to do this.

## 1 Answer

You can do it if you add a driver to the second shape key.

The first driver:

max(min(var/0.8, 1), 0)


The second driver:

1 if var>0.8 else 0

• Wow thanks! this works great, after posting this I managed to get something using the driver modifiers but it wasn't as clean as I would like. This expression makes things much cleaner when hiding the eyelid mesh. – Chris Dec 2 '20 at 4:05