# Bridge Surface
Select two sides to generate a bridged surface.
Click 
on the toolbar to open the bridge surface command dialog box, its command interface is as shown in the picture below:
The control description is as follows:
- Start edge/End edge: Pick up the start edge/end edge of the bridge surface;
1）Edge line requirements:
- Support the selection of edges of surfaces/entities, sketch non-reference lines, space curves.
- Only a segment of the edges or sketch lines can be picked up, not the entire outline. For example: Pick up one edge of the rectangle outline, pick up only the edge that was clicked, not the entire rectangle.
- Both edge lines should be either open loop or closed loop.
| Two open loops | Two closed loops |
|---|---|
 |  |
2）The direction of the bridged surface edges relative to the selected edges can be adjusted with the Edge Reverse button.
| Invert Forward | After reverse | |
|---|---|---|
| Open loop outline | |  |
| Closed loop contour | |  |
3）When the edge line is the edge line of the surface/entity, you can set the continuous mode of bridging the surface with the edge line:
Curvature (G2) : the curvature at the edge of the bridge surface is continuous with the surface where the edge line is located;
Tangent (G1) : the edge line of the bridge surface is continuous with the surface where the edge line is located;
None (G0) : there is no tangent/curvature continuity between the edge line of the bridge surface and the surface where the edge line is located, and only contact;
The weight can be set in the two ways of "curvature and tangent";
The continuous way at the two edges can be different;
Curvature and tangential mode, extending from the side line to the outside direction of the surface where the side line is to form a bridge surface, and the extension direction cannot be modified.
Starting constraint: Control the continuous mode of the bridge surface at the edge and the surface where the edge line is located, optionally "curvature, tangent, none";
End constraint: Control the continuous mode of the bridge surface at the edge and the surface where the edge is located, optional "curvature, tangent, none".