Yes, it is possible to do, here is how:
1. Go to the 3D Viewpoint, with the Curtain Wall displayed.
2. Select the Curtain Wall and click the little "Edit" tag in its lower right part to enter Edit Mode.
3. By clicking the Eye icons in the Edit Toolbox in the upper left corner of the Viewpoint, display the Scheme and hide Frames and Panels.
4. You need to adjust Horizontal Grids vertically. Click any of the horizontal Grids, hold down the mouse key and the Pet Palette appears. Select the Move Grid command (second from left on the Pet Palette).
5. Move the Grid 25 mm upward (the distance between 1231 mm and 1206 mm).
6. Now there is a Horizontal Gridline just 25 mm above the bottom boundary of the Curtain Wall. Click to select it and press the Backspace key to delete it (or right-click and use the Delete command of the context menu).
7. Click "OK" in the toolbox to accept changes.
Voilá.
Loving Archicad since 1995 - Find Archicad Tips at x.com/laszlonagy
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2x28" (2560x1440), Windows 10 PRO ENG, Ac20-Ac28