What is outside and inside reference plan for polygonal corner façade?

Each polygonal façade is constructed on mesh reference plan. In first phase of construction you work on geometrical division, defining module lengths and angles between them:

Reference plan in one of two surfaces of the glass / panel chosen for the façade: internal or external (inside or outside). When you select “inside”, the reference plan marked with red line is constructed on internal surface of the glass inserted in façade system. (Hint: to see it on the model, you can disable the visibility of some profiles and gaskets, leaving only glass visible):

When you select Reference plan as “outside”, the reference plan marked with red line is constructed on external surface of the glass inserted in façade system: