Lock Pin bone to move on 1 axis?

[amanandink]

I came across this After Effect rig example
https://dribbble.com/shots/5374495-Touc ... cial_Share
and I wanted to try the slider approach in Moho, I got most of the way there except I cant lock a pin bone to move on 1 axis only, be it x or y. Does anyone know if a way to do it?

[synthsin75]

Parent the bone to a veeerrrryyyy long bone and set that bone's angle constraint to only cover the slider range. If it's pivot is far enough, it will look like a straight line.
http://www.filedropper.com/slidercontrol

[amanandink]

hey Wes, i'm not sure I can make that approach work, this is the current mock up i have
http://www.filedropper.com/eyetestrig
the pin bones are targets for the shy bones that have smart actions on them, but i cant keep them on the line indicator

[synthsin75]

Here's how it would work in your file: http://www.filedropper.com/eyetestrigedit

The only drawback is that the long bones do get keyframed using manipulate bones on the sliders.