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In each coordinate system you also have an option to use either relative or absolute coordinates. The UCS indicator is helpful if you want to see how the UCS moves. You can display markers for the UCS and WCS via the Workspace menu, and customize the markers' appearance via the Preference page of the Program Setup (Options / Preference). The WCS indicator is always shown at the lower left corner of the screen; the UCS indicator is shown at the UCS origin.
When using the 3D Selector, the selection shell local menu and Inspector Bar provide two options that relate selected objects to the UCS (see 2D-3D Selector).
Set UCS by Selector: Moves the UCS origin to the selection reference point.
Set Selector by UCS: Moves the selection to the UCS origin (similar to the Place on WorkPlane option for 2D objects).
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Note: The 2D Selector always moves the UCS (Workplane) to the selection.
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