Element Load Specifications-Plates in Staad Pro.

Hi,

From section 5.32.3.1, Option 1 of Staad TR-Manual: If only x1, y1 is provided, the load is assumed as a concentrated load applied at the specified point defined by (xi, y1). 

Could you please tell me how do we measure x1, y1 from the center of the element in the local axis system?

Thank you