Is there a bug in Python ChLinkLockPointLine?

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Jose

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Apr 23, 2026, 8:31:32 PMApr 23

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Hello.

I am new to Chrono and have been playing with MbD and constraints using Python.

It seems to me there is a bug in ChLinkLockPointLine. When I initialize it, it seems to constrain the point to the X axis instead of the Z, which is, as far as I understand, the standard behavior among MbD solvers. It is as if the rotation matrix I give to it was internally rotated 90 deg. Something similar happens with the output forces. They are rotated 90 degrees. Is this a bug, or am I getting something wrong? I have managed to make the other joints work correctly and compared them with other solvers, so not sure if I am getting the in-line constraint wrong. I temporarily fixed it by passing a rotated ChFramed, and by rotating the output forces as well.