Apply 3D by Slope to Target

The Apply 3D by Slope to Target from the 3D Geometry Tab in the Civil Ribbon Tab is very useful to adjust Terrain models near the bridge abutments. Users can rearrange the terrain slope to match a reference and create models adjusted to reality.

Though, it is indeed a general tool used to create a tridimensional element from a line to a surface and, as a Civil Tool, originally created for expanding the Alignment to create the Corridor modeling surface, despite it might be a very simple and straightforward task for those used with these road features, for bridge engineers just starting to expand their activities to the 3D Terrain modeling it might get tricky to learn it without more detailed explanations. Therefore, this Wiki article is intended to guide users into the best practices to allow them to start learning the Apply 3D by Slope to Target tool by experimenting just doing it.

To model an abutment slope to a terrain model in OpenBridge Modeler users could follow the steps below:

1. Isolate the necessary elements for your visual reference, preferably in a 3D View:
   1. Use the Explorer Window to turn off all bridge elements but the abutments
   2. Also, turn on the terrain model, by selecting it and modifying the Properties
   3. In View, Select Wireframe, Drawing, the Model, and the Level Terrain_Design
2. Create an additional reference line from where the 3D slope will target the Terrain:
   1. At the Ribbon: in the Home Tab at Placement select a SmartLine
   2. Place the line where the new terrain slope will intersect the abutments
      1. It might include the wing walls
      2. It could be the case that users will move this line to the other abutment face
3. Ribbon: Civil>3D Geometry, preferably in a Plan View:
   1. Create 3D by Slope to Target
   2. Parameters
      1. Slope Option>To Terrain Model
      2. Cut Fill Option> Cut And Fill
      3. Start Cut/Fill Slope
         1. 2:1 slope in from of abutment entered as ½=0.500
      4. End Cut/Fill Slope
         1. This is the “Side” Slope OR the Embankment slope perpendicular to the roadway
         2. 3:1 Slope on the side entered 1/3=0.333
      5. Corner Option>Rounded
      6. Transition Type> Constant
   3. Slope Location
      1. Leave All 3 check boxes unchecked
      2. Side: Choosing “Right” always seems to work (why=unknown)
      3. Start: Program enters this when data points are clicked
      4. End: Ditto
   4. Feature Definition> Terrain Model Feature Definition Set the
4. First Prompt > Data point (left click)
5. Second Prompt: Left click on MultiLine
6. Third Prompt: Left Click on Terrain Reference
7. Continue with data clicks through remainder of prompts until it Accepts.
8. Turn off Terrain Reference (for clarity)
9. Ribbon:Civil>Terrain Model>Create Terrain by Elements
   1. Select the two Boundaries.
   2. Data clicks walk thru all Parameter to Accept

Useful links:

Online Help OBM/ORD:

3D Geometry 3D Tools (bentley.com)

Apply 3D by Slope to Target (bentley.com)

Additional 3D by Plan Profile (bentley.com)

Create 3D by Slope to Target (bentley.com)

Video fo the same feature in use at ORD (from the alignment):