e-Learning on ProfilesReference curves are entities that help you to construct a solid object (for example, an axis of rotation) and must lie in the same plane as the profile. A typical example of a reference curve is a line to be used as an axis of rotation to create a revolved sweep solid. Reference curves are always displayed using a dash-dot line type. When you create a profile by preselecting entities, any entities drawn using Line Type 4 (the dash-dot line type) are automatically converted into reference curves. When you sketch within the Profile environment, any entities created using Line Type 4 are immediately created as reference curves. You can also create a reference curve by switching to the Profile environment, selecting the entities you wish to convert into a reference curve, and then use the Make/Unmake Reference command.
Preselection is not obligatory. You can first select the command and then the entities.
Note that when you sketch within the Profiles environment or preselect entities and convert them into profiles, entities created using line types other than 1 or 4 are automatically converted to the Line Type 1 (continuous) linetype.