Dear All, I am going to simulate a five -storey high Atrium. The roof is fully glazed, I divide the atrium into three Zones but from Archives of TRNSYS mailing list I saw an E-mail from David, says lowest zone receive no solar radiation. have anyone an experience with Atrium simulation. Best Regards -- Ümit Esiyok e-mails: umit.esiyok@uni-dortmund.de