Street and crossing shapes

Street and intersection shapes generated within the CityEngine consist of different shape types. Each shape type is defined by its start rule.

Default start rules for street shapes

Standard start rules are: Street, Sidewalk, Crossing, Junction, Freeway, FreewayEntry, Roundabout, RoundaboutIsland, and Joint.

Color	Shape start rule	Created by
	Street	Street
	Sidewalk	Street, and all intersection types
	Joint	Intersections with only 2 adjacent streets
	Crossing	Crossing or Smart intersections
	Junction	Junction or Smart intersections
	Freeway	Freeway or Smart intersections
	FreewayEntry	Freeway or Smart intersections
	Roundabout	Roundabout or Smart intersections
	RoundaboutIsland	Roundabout or Smart intersections

Note:

• Shapes have by default no rule file assigned. Therefore, if you like to work with these default start rules you have to define the CGA rules "Street", "Sidewalk", "Crossing", "Junction", "Freeway", "FreewayEntry", "Roundabout", "RoundaboutIsland", and "Joint". These rules will be the starting point for geometry generation.
• For information on the Block default start rules, see Block parameters.

Street shape UV values

For details of the UV coordinates, see Street and Intersection Shape UVs.

Reset shape attributes

Since start rules can be overridden, users may want to use the Reset Shape Attributes tool to revert the start rules to the default values. To execute the tool, select a set of shapes and then choose Graph > Reset Shape Attributes from the main menu.

Conflicts

Because the internal shape creation algorithm computes the intersection shapes for each node individually, conflicts can occur. Usually, conflicts occur when the distance between two nodes is very small. In this case, at least one node is located inside the shape of a neighbor node.

Conflicting segments are marked with a red dashed line. The error color can be changed in the Viewport Preferences.

There is a conflict (red dashed line) because a street node is inside a crossing.

The conflict has been resolved by running the Graph Cleanup tool.

To resolve conflicts, you can choose from the following actions:

• Cleanup the graph, see Graph Cleanup Tool
• Edit the graph network, see Street creation tools
• Change shape creation parameters (i.e. street width), see Street Parameters and Intersection Parameters.
• Use the Edit graph network tool to edit curves, change street widths or move nodes.