No matter the SOLIDWORKS rebuild command you use, whether it’s standard rebuild (the “green light” icon) or forced rebuild (CTRL-Q), it’s important to understand what is happening when SOLIDWORKS is building a feature. When a feature is being built, the modeling engine is carrying out an instruction in the file’s instruction set. The resulting information is geometry in the design space. SOLIDWORKS will check this geometry against existing geometry in the model to make sure it “fits” geometrically. By default, SOLIDWORKS checks the geometry it is building against the adjacent faces, e.g., the faces that share an edge with the face(s) of the feature it is building. For example, when building a fillet, SOLIDWORKS checks to see if the face of the fillet fits with the faces the fillet shares edges with (“connects to”). When it fits, SOLIDWORKS moves on, but when it doesn’t an error is generated. While this level of geometry checking is generally efficient, in some cases it is not sufficient. There are cases where the face being built intersects with faces already in the model. However, there is no intentional connection; they aren’t supposed to share edges. While this will be a problem, the default level of checking doesn’t catch this because it only checks against faces in which it is supposed to connect.