The system will allways stay related to the center of the panels, but you should be able to offset the whole thing based on the reference line, but maybe you cannot set a negative value.
I think the way the reference line works is done because curtain wall systems often have different sized mullions and transoms, yet center of glass / panel is the same.
Erwin Edel, Project Lead, Leloup Architecten
www.leloup.nlArchiCAD 9-26NED FULL
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