When creating Topo in Revit, you will almost always have a few places along the edge of the Topo where the contours start to connect in some funny ways. Frequently, the contours will create a steep slope that does not exist. While this can usually be ignored since it occurs at the Topo edge, it can also be fixed with a relatively simple solution.
This steep edge effect is essentially a result of the triangulation between points and can be solved by lining up all of the edge points.
The easiest way to do this is to draw a reference plane along the edge of the Topo. You can actually do this while editing the surface. Drawing a reference plane while editing the surface will allow you to snap the plane to the surface points. But once drawn, the reference plane cannot be modified in the Surface Sketch mode.
Then, simply move or copy the points to align with the reference plane. Unfortunately the Align tool does not work with surface points, but the points will easily snap to the reference plane.
Depending on the size and slope of your Toposurface, this may take a little while, but being able to snap to the reference plane does speed up the process considerably.
Besides, it really doesn’t take much time, and the final result is well worth the effort.