About Defining Motion Zero References

Bear in mind the following limitations when defining a rotation axis:

• Point-point zero reference—The system draws a vector from each point in a direction normal to the rotation axis. The motion zero is the point at which the two vectors coincide. The points cannot lie on the motion axis.

• Point-plane zero reference—The plane containing the point and the rotational motion axis must be parallel to the selected motion zero plane. The point cannot lie on the motion axis.

• Plane-plane zero reference–The planes are parallel at motion zero. Both planes must be parallel to the axis of rotation.

Bear in mind the following limitations when defining a translational axis:

• Point-point zero reference—The distance between the points in the translation direction is zero at motion zero.

• Point-plane zero reference—The distance between the plane and the point in the translation direction is zero at motion zero. The plane must be perpendicular to the motion axis.

• Plane-plane zero reference—The distance between the planes is zero at motion zero. Both planes must be perpendicular to the motion axis.

Bear in mind the following restrictions when defining zero references:

• Planar connections—You can define point-point zero references only for planar translation axes. You can define plane–plane zero references only for planar rotation axes.

• Bearing connections—You must select a point or a plane on the body that contains the motion direction definition, that is, the line in the point-line constraint. This reference is aligned to the point that defines the bearing joint.