What are trace & reference lines? Do you mean Guide Lines? These are just temporary and I wouldn't use those for something 'permanent'. We have a guide line layer where use actual lines / polylines for that.
Otherwise floor plans by default will use the project origin. If someone moved the reference, you can reset it back to default (it's the 2nd button from the right on the Trace & Reference palette, between rotate and refresh).
Erwin Edel, Project Lead, Leloup Architecten
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