It is still common that you are given a file with just contours, no spot elevations and no breaklines. Your job is to create a DTM that will match contours in the drawing. This workflow will show you the best way to create a DTM from just contours.

Import From Graphics – Contour Point Type

1. Select the contours using a MicroStation selection set.
2. From the InRoads pull down menu 
File > Import > Surface. The Import Surface dialog will appear.
3. From the From Graphics tab.
   1. Surface:
   2. Load From: Single Element
   3. Elevations: Use Element Elevations
   4. Seed Name: Contour1
   5. Feature Style: Contour (if available or similar feature style name)
   6. Point Type: Contour
4. Select the Apply button Select OK to use elements contained in selection set.
5. Select the Close button.
6. From the InRoads pull down menu Surface > Triangulate. The Triangulate Surface dialog will appear
7. Select the Apply button the surface will be triangulated.
8. From the InRoads pull down menu select 
Surface > Utilities > Generate Inferred Breaklines. The Generate Inferred Breaklines dialog will appear.

Note: Generating Inferred Breaklines is only available when there are Contour point types loaded into the surface.
9. Select the Apply then Close buttons. The inferred breaklines will be added to the surface.
10. From the InRoads pull down menu Surface > Triangulate. The Triangulate Surface dialog will appear
11. Select the Apply button the surface will be triangulated now with the inferred breaklines.
12. Display the contours and verify how close they match.

Video Demo

See all of our InRoads tips on this YouTube playlist.