Stack two shape keys in one driver?

Hi!
For my character to blink, it has two shape keys to control the upper lid.
Because relative shape keys can only follow a linear path, the lid will cut through the cornea of the character’s eyeball if only one shape key is used. That’s why I’m using two shape keys; the first shape key brings the eyelid down halfway, and the second key (when stacked onto the first key), brings the lid down all the way.
Basis:



Key 1:


Key 2 stacked onto Key 1:

When I add single driver to control both shape keys, the driver still calculates the “Averaged value” of both shape keys, so the final transition is still really wonky.

I want the driver to calculate Key 1 when the driver bone is pulled halfway down, and then stack Key 2 onto Key 1 when the driver bone is pulled all the way down.
So when the driver bone is pulled halfway down, Key 1 has maximum effect but Key 2 has 0 effect. Then, when the driver bone is pulled all the way down, both Keys have maximum effect.

Are there any special driver settings that can achieve this effect? Thanks!!:smiley:

Sure, add a driver to both shape keys, then create custom control curves to control them.

Here… watch this:

IIRC, when I made that video, I didn’t understand the graph editor as well as I do now, so I kinda searched for where the points should be plotted.

Randy

Thanks! That is a very helpful tutorial! :slight_smile: