I've been fighting this problem for 12 years. Solidworks can't make a proper split on the silhouette of a fillet/radius/round, at least not consistently. Anybody else have problems with this? Draft Analysis shows that the split should be clean and continuous yet SW will often "jog" the split, making it useless. I have this problem with native SW models and with models from other software...doesn't matter what system modeled the part, SW can't split correctly (even though it shows the "zero degree edge" correctly in Draft Analysis).