We are investigating a potential bug with the PV 3D Shade Calculator that appears to have been introduced in SAM 2017.9.5. The problem seems to be caused by objects under the active surface. One workaround solution to the problem is to only include shading objects in the scene, but not objects below the array. Another solution is to use SAM 2017.1.17 r4 until we solve the problem.
To track progress on this problem, see:
github.com/NREL/ssc/issues/97
Best regards,
Paul.
