Elevation features have a z value defined at each point. Elevation features will display in the Profile Window when they are the current feature.
When a Terrain Model is created, elevation features form the triangle vertices. Thus when an elevation feature is modified or deleted and a Terrain Model exists the model is cleared.
Breakline Features
A Breakline Feature is an elevation feature used in Terrain Modeling to identify an abrupt slope change (discontinuity) such as the edge of a road. See Breaklines for more information.
Draped Features
Draped features (No Elevation features) have no defined z value at points. The elevation at each point is arbitrarily given the value -9999.0.
Draped Features are not used to define a Terrain Model. If a Terrain Model exists, the elevations of a draped feature are taken from the model. See Terrain Modeling for more information about the determination of elevations and TIN points for draped features.
NOTE: It is possible to change between Elevation and Draped Features using the Feature Properties dialog.