ArraynAt the moment, I have four outlets extruded on the room body and it is all defined under one outlet named selection. nI did use the share button only to unshare the inlet surface from the room body based on the initial advice. Other than that I did not share any surfaces. Should I share any surfaces?nI saw 55 problematic surfaces, which were the diffusers and outlets. If I deleted the contacts, would it cause problem to the simulation? I was afraid to delete anything cause I didn't want to do anything that I couldn;t fix. I was stuck on the contact issue for 2 days b4 extruding it.nI extruded the sketch because I didn't know how to resolve the contact issue so I thought that extruding it would be able to eliminate the problem and still allowed me to select the surface as interior. nOh I see. But it showed warning messages when I opened the setup in the bottom right console window.nAlso what does interface boundary condition means?.