On the Vertical Definition tab of the Window: definition dialog, you can specify the location of a window with respect to a wall or a plane.
Define the vertical location of the window:
- Level with respect to wall - when positioning a window opening along the wall height (the Z coordinate), there are 2 possibilities (the default is 100.0 cm from the floor level)
- the opening is located with respect to the lower wall level and measured to the lower part of the window 
- the opening is located with respect to the lower wall level and measured to the upper part of the window
- Level with respect to plane - when positioning a window opening with respect to a plane (for example, the floor rather than the story level), select the plane from the list, and then specify parameters
- Reference edge of a window with respect to the upper or lower level
- Offset from the lower or upper story level.