Using Intermediate Rigid Body with Multiple Constraints (New for 5.1)

You are allowed to apply multiple constraints to a single rigid body, which has one or more other physics objects as targets. However, this may sometimes cause conflicts, which can cause the effects from other constraints become locked.

This bus ring only has a Slider constraint (the bar is the target).	This bus ring only has a Hinge constraint (the bar is the target).	This bus ring is stuck because a Slider and a Hinge constraints are simultaneously applied (the bar is the target for both constraints).

However, by using an intermediate constrained physics prop which targets to other rigid bodies, the conflict situation can be solved.

1. Apply a primitive prop with few polygons.
   
2. Set it as a Dynamic rigid body. It will be the intermediate prop applied with constraints.
3. Apply the Slider constraint to it.
   
4. Pick the bar (Kinematic rigid body) as the target of the Slider constraint. Remember to modify the constraint limit to set a sliding range for the prop.
   
5. Apply the Hinge constraint to it.
   
6. Pick the bus handle (Dynamic rigid body) as the target of the Hinge constraint. Remember to modify the constraint limit to set a rotation range for the prop.
   
7. Set keys or puppet the bar to produce moving and tilting animations.
8. Play to simulate (You may set the intermediate prop as a dummy to hide it).

   When the bar is animating, the intermediate prop can slide and rotate at the same time by this method.