How to set up a rope-animation with local gravity - part 1
We will create a rope that is animated by regular gravity and some additional locally "weights" traveling along the rope.


In Front-view create 7 cubes with a distance of 3 units between the cubes.
Turn the inner 5 cubes into active rigid bodies with default-settings.
Turn the 2 cubes at the outside into passive rigid bodies. Of course you could also use "active", but since they wonīt get gravity, we donīt need to set them to active.
Between the cubes create spring-constraints with settings like stiffness=50, damping=50 and rest-length=2. Of course you can play around with different settings, I like to give them a rest-length smaller than the distance between 2 cubes, so the springs "pull" a bit more. At the end you should have a total of 6 spring constraints.
Select the 5 inner cubes and add a gravity-field with magnitude=20 and attenuation=0 (pretty much the default settings).
Now hit play and let the simulation run about 150 frames. The cubes should loose their energy at this point. Stop the animation. Now, move each of the 5 inner cubes just a little bit. Since they are not keyed, the next time you play the animation from the beginning, the cubes will stay in that position and you wonīt have to wait.
For all 7 cubes turn on their selection-handles. Now create a degree 3 curve with point snapping to each selection handle. Obviously, the curve should have 7 cvs.
continue to part 2