I have an assembly which consists of a closed chamber. Inside there a many components which are interconnected. I have to perform internal analysis inside the chamber. Chamber's outer wall is made from two wall of different shape assembled together. But when I tried to setup computational domain it is showing an error as non watertight model. I then tried using leak detection so found that between two assembled wall of outer wall there is a small gap on the top and bottom. How to fix this ?? I had even tried using create lids option but unable to create watertight model. Please someone help me in fixing this issue.