1. Open the drawing named lesson13.dwg which is located in your GeoTools Tutorials folder. This folder is located in the folder where you have installed GeoTools.

2. You should see a drawing (see Image 14-1) of a small layout of road under development represented by 3D Polyline.

Image 14-1

3. The vertices of the 3D polylines will have certain Z elevation or it can have zero Z elevation. So we will see how we can find the vertices which are having zero Z elevation.

Identifying zero (Z) elevation vertices in 3D polyline

1. Click on menu GeoTools => Polyline Toolset 1 => Identify zero elevation vertices or type GT_PL_0 at the command prompt. This will pop-up the standard selection dialog box as shown below (image 14-2)

Image 14-2


2. Click on the button Scan selected objects and select the 3D polyline.

3. Lastly click on Apply button. This will mark points at the vertices whose Z elevation is zero as shown below in (image 14-3)

Image 14-3

So we have learnt how to identify the vertices of 3D polyline which are having Z elevation zero. Now we will see how we can set the zero elevation vertices to nearest non-zero Z elevation.

Assigning zero elevation vertices to nearest non-zero Z elevation

1. Click on menu GeoTools => Drawing Cleanup => Set all 0 elevation vertices to nearest value or type GT_SET_Z_PL at the command prompt. This will pop-up the standard selection dialog box as shown below (image 14-3A)

Image 14-3A

2. Click on Scan selected objects button and select the 3D Polyline and press Enter key this will bring back to the standard selection dialog box.

3. Click on Apply button this will hide the selection dialog box and you will be prompted to enter the Minimum vertex elevation to be allowed specify 100.

4. This will assign the nearest Z elevation to the vertices which  were having zero Z elevation. And the following message will be displayed at the command prompt as shown in image (14-3B)

Image 14-3B

After learning how to assign nearest Z elevation to vertices having zero Z elevation. Now we will see how we can place blocks representing Trees along the road at variable measured distance.

Placing blocks to represent (Trees) along the road at variable measured distance

1. Click on menu GeoTools => Build => Multi-Variable Measure or type GT_MVMEASURE at the command prompt. This will pop-up the dialog box as shown below (image 14-4)

Image 14-4

2. Under Specify segment length  choose Cumulative - From beginning of line.

3. Check the boxes Place blocks at measured points and Align block with object.

4. Click on the Select button to choose the block. This will pop-up the dialog box as shown below in (image 14-5)

Image 14-5

5. Select the TREE block and click on OK button this will bring back to the previous dialog box.

6. Now press OK button on the Multi Variable Measure dialog box. You will be prompted to select Line or Polyline select the 3D polyline 

7. After selecting the  3D polyline you will be prompted to specify the measured distance from start so enter the below mentioned distances when prompted.

8. i) 600 ii) 1000 iii) 1600 iv) 2400 v) 3600 vi) 5000 vii) 6000

9. After entering all the above distances press Enter key to end the command. And this will place the block TREE on the 3D Polyline at measured distances as shown below in (image 14-6)

Image 14-6