About Motion Axis Settings
You can specify the relative orientation or location of the two parts connected by a motion axis:
A rotation motion axis will read zero when the zero reference planes on the two parts are aligned. The zero reference plane for each part is a plane that contains the motion axis.
In a translation motion axis, the zero reference planes are aligned. A zero reference plane is the plane that is perpendicular to the motion axis and passes through the motion point.
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A motion axis zero reference can only be set for a motion axis servo motor. You cannot create more than one motion axis zero on any connection. Motion axis zeros are not required for any servo motor, but if they are not set, an arbitrary reference is chosen on each body, with unpredictable results.
Motion axis zeros and motion axis range limits can be set for all connection types except a ball joint.
For more information about motion axis settings, search the Help Center.
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