Blocking and Shading efficiency

In SAM how we incorporate the blocking and shading efficiency of heliostat field? Is it part of the ratio of reflective area and is used to estimate the total area of heliostat?

SAM's power tower models calculate the heliostat field shading and blocking effects as described in Section 2.1.1 of Wagner, M. (2008) Simulation and Predictive Performance Modeling of Utility-Scale Central Receiver System Power Plants.
You can find a link to that and other model descriptions on the Performance Models page of this website.
Best regards,

Paul.