CityEngine offers a suite of intuitive tools that allow you to create and edit graph networks. You can do the following with these tools:
- Create graph networks with street creation tools.
- Use the selection tool to select street nodes and edges. The selection displays in the Inspector, in which you can edit the attributes.
- Modify graph segments and nodes using the transform tools.
Street creation tools
You can use the Freehand street creation tool 
(Shift + G) and the Polygonal street creation tool (G) for drawing streets manually on the fly.
Snapping
Use the Guide Creation tool 
to set guides to snap to as you create the streets. This allows you to align streets accurately to other features. See Create guides for more information.
Street creation settings
You can configure the settings when creating new streets using the Street Creation Settings option. Click Graph > Street Creation Settings... from the main menu.
Settings include street width, block subdivision type, automatic graph cleanup, alignment to terrain, and model generation. Use presets to store a number of brushes, which are stored individually for each scene.
The following tables list the parameters:
General
Re-use settings from neighbors | If enabled, settings are copied from neighbor streets, if available. If an existing street is extended, settings are typically copied from that segment. |
Apply graph cleanup | If enabled, the graph cleanup tool is executed after each editing operation. Note that the settings for graph cleanup can be controlled by clicking Graph > Cleanup Graph... from the main menu. See Cleanup Graph Networks. |
Align terrain | If enabled, terrain layers are automatically aligned to new streets. |
Street
Street width | The street width. |
Street center offset | The offset from the centerline of the street. The offset direction is perpendicular to the street direction. |
Left sidewalk width | The left sidewalk width. |
Right sidewalk width | The right sidewalk width. |
Precision | The precision for shape creation. |
laneWidth | Determines the approximate width for lanes. Used for the automatic setup of UV texture coordinates on dynamic street shapes. |
See Street Parameters for more information.
Block generation
Subdivision type | The subdivision type for shape creation of new blocks. |
See Block Parameters for more information.
Rule-based model generation
Rule file | If set, this rule file is assigned to all new street shapes. |
Apply rule-based model generation | If enabled, model generation is automatically triggered. |
Additional graph tools
CityEngine also includes additional tools to help with creating and editing streets, such as the Edit streets and curves, Cleanup streets, and Align streets to terrain tools.