# Getting hinge constraint to work with rigid bodies

Simple scene with two cubes and a plane - one cube is fixed, one has mass and has a hinge constraint.
In the settings for the hinge constraint, there are two settings for objects. I set one to be the fixed cube, but not sure what to do with the other. Thinking in real world, a hinge connects only two objects, so it isn’t clear to me what the 2nd object should be. I also have a Wind force set up thinking the cube with the hinge constraint will ‘flap’ in the wind, but it simply slides along the plane, but I do see a dashed line between the two cubes. Any advice on proper set up?

Thanks.

I think you will need to explain more clearly what you are trying to do. If you have 2 cubes that are hinged together the cube with the hinge constraint should be a passive rigid body and the cube that is going to move should be an active rigid body. On the passive cube, add a hinge constraint and object 1 will be the passive cube and object 2 will be the active cube. If you add a Wind force it will blow the active cube around the passive cube. You should remember that the Z-axis is the axis of rotation of the hinge constraint. here is an example.

hinge.blend (534 KB)

Thank you for the file. That is exactly what I was trying to accomplish. However, with some simple experimentation, I noticed the physics engine does not take into account the profile of the mesh object. In other words, if I scale down the cube to be very thin along the axis perpendicular to the wind force, the cube still ‘flaps’ in the wind as much as in its original form. I may need to try the test with a clear fluid.

If you scaled the cube in object mode you might want to apply the scale (Ctrl-A and choose scale) and see what happens