Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
Assuming you're referring to OpenStudio/EnergyPlus, you'll find some good answers in past UMH posts (search for "massless", "nomass" or "no-mass"). Indeed, some E+ modules (e.g. KIVA, Site:GroundDomain:Slab) won't take in massless materials (edit: initial comment re-posted as an answer).
