The native InRoads surface tools contain a command named "Generate Inferred Breaklines" which was used to smooth a DTM created from imported contour graphics. The OpenRoads Terrain Modeling tools do not require this functionality when importing a terrain from contour graphics. The video below demonstrates how the OpenRoads terrain model correctly triangulates contours imported from graphics.

Click the video below to play it. To view in fullscreen mode, first click the YouTube link at the bottom of the video to launch the video on the YouTube site. Then, click the fullscreen button (rightmost button at bottom of video).

 Recorded in 1280 X 720 resolution.