See screenshots and files below. When a Face, coming from an Floor object in Revit, which is not aligned with the main WCS X-axis, is connected to the Surface.PointAtParameter node, then the points are generated according to the global Dynamo X-axis and on the XY boundary box of the face. When the same script is done on a Face selection of a wall, which is also not aligned with the X-axis, then the points are nicely generated within the curves of the vertical face.
Anyone an id ea how the generate the points on the XY surface so it follows the red arrows indicated in the picture below?
These are the datasets: