Edit street and curves

The Edit street/curves tool Edit street/curves tool provides handles to edit nodes by moving them, changing curvature, and adjusting the height of the nodes.

To edit nodes, click the Edit street/curves tool Edit street/curves tool (C) or click Graph > Edit Streets/Curves from the main menu.

Node editing

Each graph segment has two curve handles, one attached at the start and end nodes of the segment. The green handles drive the start and end direction of the street. The yellow circle allows you to move he node.

Curve with two nodes selected

To edit either the horizontal or vertical components of a curve handle, change the viewing angle relative to the segment node. A steep angle allows you to edit the horizontal component, with a glancing viewing angle of the vertical component. The dashed blue line (which is only visible when you hover over one of the curve handles) indicates the local weight of the curve. To lock the direction, press Shift before dragging a curve handle.

Curve handles
Curve handles are shown.

The green circle of the curve handle indicates the smoothing type of the node (manual direction, straight, or smooth). Clicking a green circle while pressing the Ctrl key switches between the types.

The images show the indication of node type in a green circle: (left) smooth with manual directions (middle) straight (right) smooth with automatic directions

Smooth with manual directions handle
Smooth with manual directions handle
Straight handle
Straight handle
Smooth with automatic directions handle
Smooth with automatic directions handle
Note:

  • The spline is mathematically defined by the two end points of the dashed blue lines, plus the segment's start and end points.
  • The segmentation of the street shapes defines the segmentation of the neighboring lot shapes. The overall number of segments per curve can help you avoid issues such as narrowly subdivided facades. The segmentation can be adjusted using the Precision parameter in the Segment Parameters or Node Parameters sections in the Inspector window.

Principle street handles

When an intersection has the type Freeway or Junction and has three or more connecting streets, the curve handles are accompanied by principle street handles. These allow the principle street at an intersection to be edited, changing the intersection geometry.

Dark green principle street handles on the left side of intersection
Dark green principle street handles on the left side of intersection.
Dark green principle street handles on the right side of intersection
Dark green principle street handles on the left side of intersection

Specify the desired principle streets by dragging a principle street handle from one street to another.

Note:

Dragging any principle street handle into the yellow circle with clear the principle street at the intersection results in the default behavior.

Straight versus smooth

Streets can be created either straight (default) or smoothly curved. To switch between the two states, click Graph > Set Curves Straight and click Graph > Set Curves Smooth in the Graph main menu.

Set Curves Straight
Set Curves Straight
Set Curves Smooth
Set Curves Smooth

To automatically choose between those types, you can use Graph > Curves Auto Smooth. Here you have two parameters:

  • Threshold angle determines the minimum angle for curve smoothing.
  • Horizontal optimize set streets in front of slopes to straight to prevent oscillations.