Viewsheds

Viewsheds are visualizations of what is visible from a given point and are often used in urban planning. Use the Viewshed Creation tool when you want to determine the visible area from an observer point to a point of interest. The tool colors areas that are visible (by default in green) or occluded (by default in red) from the observer. The viewshed object you created can then be managed in the Scene Editor.

You can open the Viewshed Creation tool the following ways:

• Click the Viewshed Creation tool .
• Click Analysis > Viewshed Creation in the main menu.

To open the Tool Options window , click Window > Tool Options in the CityEngine main menu.

Create a viewshed

To create a viewshed, do the following:

1. Click a point in the Viewport to create an observer point.

   This starts the Viewshed Creation tool , which dynamically displays the viewshed as you move.

2. Drag the tool to set the point of interest.
3. Click again to anchor the Point of Interest property in the viewshed.

   The viewshed is added to the Scene Editor and is automatically selected. You can directly adjust its properties, such as the Angle of View and View Distance parameters, in the Viewport using handles or in the Inspector using input fields.

   

Tool options

The Tool Options window includes the following settings:

Viewshed Creation
Horizontal Angle of View (°)	The value determines the horizontal angle of view for the next view corridor placed. Once placed, you can adjust the viewshed.
Vertical Angle of View (°)	The value determines the vertical angle of view for the next view corridor placed. Once placed, you can adjust the viewshed.

Adjust the viewshed

You can adjust the viewshed in the following ways:

• In the Viewport, you can drag any of the orange handles to modify the Observer point, Point of Interest, or Angle of View properties.
• In the Inspector, you can edit any of the properties.

Properties

The following is a list of the Viewshed Creation tool properties in the Inspector:

Horizontal Angle of View	Horizontal angle of view, or field of view, from observer
Vertical Angle of View	Vertical angle of view, or field of view, from observer
Observer Point X	X-coordinate of observer
Observer Point Y	Y-coordinate of observer
Observer Point Z	Z-coordinate of observer
Tilt Angle	Camera view angle from -85 to 85 degrees
Heading Angle	Camera view angle from -360 to 360 degrees
View Distance	Distance between observer and point of interest

Tip:

The Colorize Scene property in the Inspector allows you to choose whether to display the colorized visible or hidden areas in the Viewport. The preview shows you the view from the observer point with the current properties, enabling an intuitive placement of the viewshed.

Analyze by layer

The Inspector displays visibility statistics about the current viewshed and breaks the visibility down by layer. See Visibility by layer for more details.