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Creating Breaklines

Updated July 09, 2021

This article applies to:
  • Terrain 3D
  • Terrain Forestry
  • RoadEng Civil
  • RoadEng Forestry
This Knowledge Base article is an excerpt from one of our tutorial files. The files referenced in the article, as well as the full tutorial document, are available in our Tutorial Installer.  

As seen in Importing ASCII Survey Data, breaklines can be created automatically. Sometimes, however, it is easier to simply connect the dots. In this exercise, you will add some breaklines to a data set that consists of nothing but points.

To perform this task, you will learn about the following Terrain functions:

  • Select features by name.

  • Join points to create a polyline feature.

  • Create a new feature.

  • Draw and edit features with the mouse.

  • Format feature colors, symbols and line styles.

Note: Refer to Getting Started section for file install folders (<RoadEngCivil> and <Defaults and Layouts>).

  1. Open the Terrain Module.

  2. File | Open <RoadEngCivil>\DTM\Topo no breaklines.terx.

Figure 1: 3D and Plan Windows, File: Topo no breaklines.terx.

Notice that the road is not well defined. As shown in the previous exercise, breaklines are required to define the surface realistically. It would also be nice to see other surveyed features like pavement edges and the road center line. Fortunately, the survey data for this file was imported so that features are named by the survey point code (see exercise Importing ASCII Survey Data).

Selecting Features by Name

  1. Hover your mouse cursor over a point in the Plan window and note the information tooltip window that appears after a moment (see figure above). This is a subset of the Status window information available after you select a point.

  2. Zoom in and select or hover over points to find out their names. You will notice that the road center line points are named “CLP”.

  3. Right Click…| Select Feature(s) | By Name… | Advanced… button to open the dialogue box. Expand the dialogue box as shown below.

Figure 2: Select Features by Name Dialogue Box
with the Select Matching Names area Visible

  1. Press Un-Select All button in the center of the dialogue box.

Note: The Select features by name dialogue box allows you to add/remove feature(s) to/from the existing selection set. This can be very powerful if you want to select a group of features that don’t share the same name. However, most selection operations will start with Un-Select All (if the initial number selected is not zero).

  1. Press Advanced… button | type “CLP” at the top of the Select Matching Names area | press Select button underneath on the right-hand side. Note that the number Selected is now 69 and that the CLP items are checked in the list (you may have to scroll down).

Figure 3: Select Features by Name Dialogue Box with CPL Selected

  1. Press OK to accept the change and close the dialogue box.

Joining Points to Create a Polyline Feature

Now that the CLP points are selected (highlighted magenta) we can connect them together and format the resulting polyline.

  1. Feature Tools | Join or <Ctrl-J>, to connect all the CLP points into one polyline feature. When warned, “existing triangles will be cleared”, respond OK button.

Modifying Feature Formatting

  1. Right Click in plan view| Modify Selected Feature(s) | Linetypes, Symbols or <Ctrl-L>, to display the dialogue box below.

Figure 4: Feature Formatting Dialogue Box

  1. Within the Plan Window Feature Formatting set Symbol Type: None, the Line/Border Type: 3-dash-dot and the Color: red as shown in the figure above.

  2. Press OK to accept the change and close the dialogue box.

The center line is now visible and represented by a polyline as desired. It should also be a breakline as it represents the crown of the pavement.

  1. Use Feature Properties in status window or <Ctrl-E> dialogue box to set the CLP feature as a breakline (as in the Finding and Repairing DTM problems exercise above).

  2. Now let’s try the same process with the edge of pavement (EP) points.

  3. As in step 5 above, use the Select features by name dialogue box to select all EP points.

  4. Again use <Ctrl-J> to join them. The results are pictured below.

Figure 5: Pavement Edges Connected using the Join Function

The polyline created above connects one side of the road to the other; the join function connects each point to its nearest neighbour. If the points had been coded EPL (left) and EPR (right) then this procedure would have produced satisfactory results (in two operations).

In this case, it is easier to connect the dots. We will make the EP points easy to find and then create a new breakline feature to connect them manually.

  1. Use the undo button or <Ctrl-Z> to restore the loose points.

  2. As in step 10 above, use the formatting dialogue box <Ctrl-L> to change the EP points to a distinctive color and symbol (as below).

Figure 6: Formatting can Make it Easier to Locate Points of a Given Type

  1. Select the Terrain Modeling | Delete TIN. Check the Delete Contours box and press OK button. This will make the following steps easier.

Creating a New Feature

  1. Home | New Feature.

Figure 7: The Feature Properties Dialogue used to Prepare a New Feature

  1. Change the Name: EP-BL and check the Breakline property box as well as the others shown in the figure above.

  2. Within the Feature Properties dialogue box press Mouse button to close the dialogue box and create the new feature.

  3. When you are prompted to define the Elevation value, just press OK | keep Default elevation: 100.0. We will be snapping to existing points and picking up their elevations.

Drawing with the Mouse

When you are in Edit/Insert points mode, the mouse cursor will change to indicate what will happen when you click the mouse.

New point is added at either end of the current feature.
New point is inserted in between existing points of the current feature.
Existing point is captured for editing.
  1. Your mouse cursor has changed to a pencil indicating that you are in Edit/Insert points mode. Left click anywhere in the Plan window (mouse down and up again) to create a new point. Your cursor changes to a cross.

  2. Move the cross over an EP point the cursor changes to indicate you are ready to snap. Click a second time to anchor the new point. Note that the Elevation shown in the Status window is the elevation of the EP survey point (if it is 100, then the snap failed – you may have been too far from the EP point).

Note: Snap to Point is an option set in the Plan window options Right Click | Active Window (Plan) Options | General tab). Settings like this are saved in the document and in screen layouts.

  1. Continue adding points to your new break line:

    1. Click with the pencil cursor to create a new point.

    2. Move the red cross over an EP point and click a second time to anchor the new point.

  2. Try editing a point:

    1. Move your mouse over an existing point in the new feature; note that the cursor changes to a box .

    2. Click the mouse the capture the point.

    3. Move the red cross to a new position and click a second time to re-anchor the point.

  3. Delete a point:

    1. Move your mouse over an existing point in the new feature; note that the cursor changes to a box .

    2. Click the mouse the capture the point.

    3. Type the <delete> key.

  4. Insert a point:

    1. Move your mouse over an existing segment in the new feature; note that the cursor changes to a pencil with a cross .

    2. Click the mouse to create a new point.

    3. Move the red cross to a desired position and click a second time to anchor the point.

  5. Stop when you have done enough points to get the hang of editing with the mouse. Make sure you have tried deleting and inserting points as well as adding new ones at the end of the feature.

Note: You can edit the points of any feature. First select the feature, then right click and select menu Edit/Insert points with mouse (you can also choose the pencil button in the Home tab| Mode group | Tool Selection button | Edit/Insert Points with Mouse from dropdown menu.

Your new feature should look similar to the figure below. Note that the new breakline (EP-BL) is separate from the original survey points (EP) although its vertices share the same coordinates.

Figure 8: New EP Breakline Feature

There is another way to connect the dots that is similar to the first method used to connect the CLP points. You will now create a breakline for the other side of the pavement.

  1. Change back to selection mode : Right click |select menu Select with mouse.

  2. Click on one of the EP points to select it (the point will turn pink).

  3. <Shift> click on the next EP point: hold the <shift> key, left click on the EP point, release the <shift> key. Now two points should be pink.

  4. Type <Ctrl-J> to join the two points. Now you have a two-point polyline.

Figure 9: Joining Points a Few at a Time,
Select a Few Points (<shift>+ right click), then Join Them <Ctrl-J>

  1. Make sure the new two-point polyline remains selected and <shift> click to select a few more EP points (left side of figure above). It doesn’t matter which order you select the points.

  2. Type <Ctrl-J> to join them all into a bigger polyline.

  3. Continue this process until you are comfortable with the process. Then set the properties of the new polyline to Breakline <Ctrl-E>.

If time permits you may wish to create breaklines for other point types using any of the methods above.

  1. File | New. Do not save changes.