I want to drop a Padlock object that not only bounces the main body of the lock but has an open lock that also swivels when it hits.

I can't do this with a parent child relationship since it isn't calculated in the simulation... any ideas?


1 Answer 1


It sounds like Rigid body constraints are what you want.

For a padlock you most likely want a Hinge constraint, to allow rotation on only one axis.

Creating a Rigid Body constraint

3D view > Tool Shelf > Rigid body tools:

enter image description here

This is the easiest way (currently) to create RB constraints. (Select objects and press Connect. all selected objects have to be Rigid Body objects to do this.) This will create an empty that represents the constraint. (Constraint settings are in the physics panel)

enter image description here

A quick setup, frame 1 and frame 50:

enter image description hereenter image description here

Note that the orientation of the empty refers to the orientation of the "hinge" (what direction it's allowed to rotate in.) by default the hinge will be allowed to rotate around the local Z axis of the empty.


enter image description here

  • 1
    $\begingroup$ Long ago I created demo video that illustrates the behavior of several of the physics constraints: youtube.com/watch?v=r6JNh-i-uVI $\endgroup$
    – Mutant Bob
    Commented Nov 1, 2014 at 20:09

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .