Edge Entity Data Format
The edge entity contains data about the boundary between two trimmed surfaces. This data includes the IDs of the two surfaces, the direction of the edge with respect to the clockwise boundary traversal of the surfaces, and the uv points of the boundary segment represented by the edge in each surface. The uv points are in groups of four. The first pair of points is the u- and v-coordinates of the edge in surface 1, and the second pair is the coordinates of the edge in surface 2. Each edge is represented by the same number of points in both surfaces and has a corresponding curve entity included in its data section. The IDs of the two surfaces are consecutive. Individual curves are described below.
Edge Topology Data
Edge topology data consists of all data which describes how the edge represents a specific portion of the boundary between two surfaces.
Data format:
Identifies surfaces connected to the edge
Direction of the edge in either surface. This is 1 if the edge is oriented in the same direction as the surface boundary, -1 if it is oriented in the opposite direction.
uv_points[ ][4]
Array of boundary points
uv_points[i][0] = u in surface 1
uv_points[i][1] = v in surface 1
uv_points[i][2] = u in surface 2
uv_points[i][3] = v in surface 2
Type of curve represented by the edge
(curve structure)
Corresponding 3D curve
uv_curves [2]
(component structure)
Curves on each side surface