Scale

Use Document > Floor Plan Scale (the command varies depending on the window)
To make a zoomed view match the view at the currently set scale, choose View > Zoom > Actual Size after setting the scale.
Model Size elements are rescaled along with the model whenever you change the project scale. Model size elements include all construction elements such as walls, objects, slabs etc.
Paper Size elements are printed or displayed on the screen at the size you specify, regardless of the scale selected for the Project. For elements that do not have any real size, such as dimensions and arrowheads, you can specify a fixed size defined in either points or millimeters.
Either Model Size or Paper Size: The following elements may be either model size (scaled with the plan) or paper size (scale independent):
The Text and Markers options enable you to reduce/enlarge text and markers as the printing scale is changed, or keep them at a fixed (paper) size.
Drawings based on an ARCHICAD view have a Drawing Scale. By default, this Drawing Scale is the same as the Original Scale (the scale of the Drawing’s source view), but you can customize the Drawing Scale in Drawing Settings.