We learned how to do an animation of this flywheel with constrains
First is to create the base model.
I created two locators, and snapped them to the center point of the two small pistons. Moving the flywheel locator under the flywheel is to let the locator follow the flywheel when it rotates.
The principle of doing constrain is to select the target that will take control first. I used aim constrain and point constrain to allow each part follows the movement of the flywheel one by one. I aim constrained the piston locator with the piston group first, and then I aim constrained the flywheel locator with piston sleeve group, lastly I point constrained the flywheel locator with the piston group.
The Belt
Next, I created the belt with a pipe polygon and stretched it into a belt shape. It’s very tricky to align the vertices with the two handles. I need to rotate some vertices more towards the center to smooth it. It took me some time to align the vertices.
Texture
I created a grid in hypershade and increased the value of Repeat UV to 40. In UV Editor, in order to make sure it’s nice and clean, the edges need to be scaled inwards to be straightened. The UV shell was scaled and rotated to fit the grid.
There was a problem that the texture was stretched if I smooth it. That is because the subdivision is not enough, so I inserted a couple of edge loops to smooth it.
Although it looks good on this side, the other side is not perfect. It still has the same problem and I don’t know how to solve it.
Animation
A tricky way to animate the belt is to animate the texture, just to key the value of Offset. So there will be only the texture moving, but it looks like the belt is moving.
In Shape Editor, I created a top bend shape and a bottom bend shape. I dragged the vertices of top bend down, and the vertices of bottom bend up. I want to make the two points move up and down while the belt is moving, so that the belt will not be moving mechanically, and it will look more realistic. I set keys for the two bends, and I added more keys in Graph Editor.
Now it moves more like a real belt, and it looks elastic and smooth.