Robot lets you define offsets in 3 coordinate systems: global, local and local - translated. The following image shows the difference among the offset definitions for the 3 coordinate systems.
Captions in the image:
AB - Bar in the initial position
A'B' - Shifted bar
local x, local z - Axes of the local coordinate system
UZ(A)+ - Positive translation value of point A with respect to the Z axis of the global coordinate system
Uz'(B)- - Negative translation value of point B with respect to the z axis of the local coordinate system associated with the translated bar
If an offset is defined in the global coordinate system, components of the bar (bar section) translation vector AA' and BB' are determined in the global coordinate system.
If an offset is defined in the local coordinate system, components of the translation vector (of the bar section) AA' and BB' are determined in the local coordinate system of the translated bar.
If an offset is defined in the translated coordinate system, components of the bar (bar section) translation vector AA' and BB' are determined in the local coordinate system associated with the translated bar.