Here is what I do (Windows), if I want to offset a copy of multiple connected segments, a polyline or polygon:
1. ALT+click the existing element (this way you will activate the element tool and get the existing element attributes)
2. activate the offset tool in the command box (or use a keyboard shortcut for that tool, which I have defined in my shortcut scheme)
3. SPACE+click on the existing element (this way you'll define the offset path) and move the cursor in the direction of the wanted offset
4. press R (my shortcut and I think the default one for relative distance) and type in the wanted distance value
The above works with all linear or polygonal elements (lines, arcs, polylines, walls, fills, slabs, ...).
If it's just one element segment I prefer a quick element copy and manual offset by moving (or streching the copy if it's an arc segment). Everything with keyboard shortcuts (copy, duplicate, (or move a copy), perpendicular to,...), which roam to every new version of archicad with my pre-defined work environment.
Probably most of long time Archicad users who know most of what Archicad has to offer, have their own way of doing things, as there is usually more than one way to achieve a specific goal. You just need to find one that works for you best.
| Archicad 4.55 - 27
| HP Z840 | 2× E5-2643 v4 | 64 GB RAM | Quadro M5000 | Windows 10 Pro x64
| HP Z4 G4 | W-2245 | 64 GB RAM | RTX A4000 | Windows 11