[ODE] vertical and horizontal hinge joint application

[Jacek Mazurkiewicz]

I have an unexpected problem in very simple simulation involving three
boxes and two hinge joints between them.
The lower hinge joint is set with a vertical axis:
    dJointSetHingeAnchor (hinge1, 1.0, 0.0, 0);
    dJointSetHingeAxis (hinge1, 0, 0, 1);
The higher hinge joint is declared with a horizontal axis:
    dJointSetHingeAnchor (hinge2, 1.0, 0, 1.8);
    dJointSetHingeAxis (hinge2, 0, 1, 0);
When I try to apply a torque to Hinge1 (vertical joint between two lower
boxes), the lowest box turns, not the two upper ones. When I switch Hinge 2
to vertical axis, I can turn any of the three boxes I want.

I guess my question is:
Why introduction of the hinge joint with horizontal axis blocks the
rotation around the vertical axis potentially provided by another joint?

I suppose that the explanation is very simple for an experienced ODE user.
So let me ask for advice.

Best Regards,
Jacek Mazurkiewicz


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