This week, I have learnt how to do a simple rigging with locators and constraints. Only using one keyframe, all the motions seem convincing with rigging.

Also, I have learnt to animatic the texture on the object instead of the object itself, to create a belt conveyor. It is convincing to trick the eyes of audience that the belt conveyor is moving.

Then, same principles applied to my own engine. The U-shape objects has to always pointed to the hexagon gear, no matter it goes ups and downs. Therefore, a locator is set at the gear centre, which then U-shape is constrained to the movement of the gear.