You can edit the Backgrounds properties in the Auxiliary objects section of the Object Inspector.
You can edit parameters of backgrounds in the properties table in the lower part of Object Inspector.
Use the options in the View dialog to toggle independently the visibility of all backgrounds in projections and 3D views.
To toggle the visibility of a background, select the General > On: Yes or No option in the background properties in the Inspector pane.
Useful information concerning work with a background:
The cursor is located at the middle intersection points of 2 pairs of parallel lines (such as a wall corner). It lets you easily define walls that are drawn using 2 parallel lines on the background and defined in a model using a central line. Lines that are taken into account to specify central lines, are highlighted when the cursor is near the intersection of their central lines. To ensure that the cursor snaps to central lines efficiently, clear the Grid option in the Snap Settings dialog.
Use the Adjust to background option in the Walls dialog to automatically specify the wall (panel) thickness, if is defined using central lines. A new label is assigned the same material as for the previous thickness.
If selected, a background is automatically updated after making changes in a file. If a DXF/DWG file location changes, specify a correct path using the background properties in the Inspector pane.
If Link is cleared, a DXF/DWG file is loaded to an RTD file and is not updated.