A graphic linear feature can be any MicroStation graphical element and is not tied to any survey point features. These have a property type of Graphic. Editing consists of using any MicroStation edit tool. The symbolization of these linear features can be controlled by the assigned feature, but assigning a specific feature is an option - not a requirement.
Surface triangles created from the raw data files - The surface is generated automatically based on the surface settings of the imported point features and linear features.