: Always separate your reference geometry (points, planes, lines) and surfaces from your solid features by organizing them into clearly labeled Geometrical Sets .
It sounds like you’re referring to , author of CATIA V5 Advanced Parametric and Hybrid Design (or similar training materials), and specifically asking about a solid post-processing step after working with patched surfaces in a hybrid modeling context. ghionea j catia v5 advanced parametrichybr patched
: A twisted surface loop where the geometry crosses through itself, preventing a solid volume from computing. : Always separate your reference geometry (points, planes,