Can I control an object using a driver with multiple inputs? I'm trying to set up a facial rig, and I want to control each eyelid with a control object, or both using a slider.

I have set up a simplified example where a slider moves both eyelids together. How do I set it up so I can also move the controls to move each eyelid?

I'm thinking that it should use the maximum input of either the eye controls or the slider. I also experimented with custom values, but didn't quite get it.

In my actual project it uses shape keys to close the eye lids, but the principle should be the same as this example.

Here's the blend file:


And here's what the example looks like:
I got it working like I wanted to:



Upper eyelid

Just add both values (slider and ctrl_up) as variables and use Type: Minimum Value, since they are going from positive to negative and we want the smallest one.



Lower eyelid

Just add both values (slider and ctrl_down) but use Type: Scripted expression, and invert var2, so when it moves up, it still gives a negative number.



Here's the final blend:


Hope this helps someone with understanding drivers!