For all GDL objects, you can select which hotspot acts as origin for scaling. You can do it in the settings dialog preview pane. Simply add a hotspot in the place that you want to use as origo.
If you need the default behaviour of your object being to scale from the origo, you have to do the transformations in the code, after mul2 move it half the new size to downwards and left.
Another way to do it: before Save As, move the drawings center to the project origin, it will be saved relative to that position.
Péter Baksa
Library Platform, Software Engineer
GRAPHISOFT SE