How to create a parametric design

Editor → Future Design (Ribbon tab) → Parametric (Ribbon bar) → The Parametric Design to edit (Left panel)

How to create and use a Parametric design:

Click on the Future Design tab
Hover over the Parametric Design button and choose Add road aligned or Add spaced design. In the left panel a new Design is added.
Select the Design in the left panel and click on the Functions tab in the right panel. Select the desired functions. These will be type of Constructions placed by the design.
Adjust the parameters in the Road and Plot tabs.
Click on the Draw Area button in the right bottom corner and draw the area for the design in the 3D world.
Then adjust the parameters in the Design tab.
Click on Generate Design.
Verify that the selections in the 3D world and the information in the pie chart look like the desired result. If not, tweak the parameters (in the Design tab) further.
Either apply the design to start a Test Run or click on Save to Current to construct the Design in the Current Situation.
Verify that the result is correct. If not, revert the application by clicking on Revert last Design and tweak the configuration further (this step is not possible when having the design saved to Current).

Save to current: a test run is not started. Instead it is applied to the Current Situation. This method is not easily reversed.
A parametric design can only be generated on an empty Terrain. Remove the existing Constructions first or choose an undeveloped area for your design.
Tip: use the Polygon pick selection tool to draw the area for the design.

See also