I’m in the process of prototyping future model where I need back and forth movement. The first draft has a this pad on the top of the box moving smoothly back and forth. It will be easy to use this starting point to make a character come to life, just so long as the character needs to move back and forth. Smoothly.
Inside the box, a crank drives a con rod which in turn pushes the slider back and forth.
It all fits together quite neatly! I’ll be making this available as a download shortly.
Here’s the prototype in animated action.