Several feasibility, compatibility, and precedence rules refer to the LIES_OUTSIDE relation (under GCD Relations in the Geometric Cost Drivers pane). If one GCD, feature-1, lies between another GCD, feature-2, and the main surface, we say that feature-2 lies outside of feature-1, that is, there is a LIES_OUTSIDE relation whose value for First is feature-2 and whose value for Second is feature-1.