Building Opi-Robo was a technical assignment for one of my grandchildren. I thought it was a nice challenge for Bongo.
2 Separate models were used, one for the compiling of Opi-Robo and a second for the walking sequence. The resulting footages were joint in post production.
The ‘built’ model (Opi-Robo Built.3dm - Google Drive) applies plain old Bongo 2.0 techniques. Nuts are Hierarchically linked to the bolt, and Expressions are used for the correct rotation of the nuts. The creation of the wires is realized by using History on a Rhino ‘Sweep 1’ system.
See also https://youtu.be/5RjyxaJgBFg?feature=shared
In the ‘move’ model (Opi-Robo Move.3dm - Google Drive) the wooden elements are Physics enabled and linked with Connections. The 2 spindles linking the sprockets to the corps are keyframed to act as motors.
In Bongo’s Document Options the ‘Use render ground plans as floor’ is set.
The other elements do not play any role in the Physic behaviour of the robot, hence they are not Physics enabled and simply linked to the corps by a Hierarchical parent/child relation.
Expressions manage the rotation of the gears in the gearbox.