Cleanup graph

CityEngine 2023.0    |    |  

Imported, merged, or self-drawn graph networks may contain the following:

  • Duplicate or close-by nodes
  • Duplicate or close-by segments
  • Intersecting segments that do not have nodes where segments intersect

These graph networks produce a number of problems when creating street shapes or extracting lots.

Note:

You can use the Cleanup graph tool Cleanup graph tool for fast cleanup of graph networks by merging nodes, merging segments, and creating nodes at intersecting segments.

You can run the tool in the following ways:

  • Click the Cleanup graph tool Cleanup graph tool.
  • Click Graph > Cleanup Graph from the main menu.
Note:
This tool operates on a selection of graph segments. Unselected segments stay unchanged. When merging, the nodes of the selected segments are merged.

Cleanup options

The checked operations (intersect, snap, merge, and resolve shape conflicts) are run one after another. The following options can be set:

OptionDescription

Intersect Segments

When checked, creates a new node at the intersection of segments.

Snap Nodes to Segments

When checked, nodes snap to segments.

Note:

Nodes with smaller street widths always snap to segments with larger street widths. Node street width is defined as the maximal street width of the adjacent segments.

Horizontal Snapping Distance

The maximal horizontal distance between a node and a target segment. This option is only relevant if the Snap Nodes to Segments option is checked.

Vertical Snapping Distance

The maximal vertical distance between a node and a target segment. This option is only relevant if the Snap Nodes to Segments option is checked.

Merge Nodes

When checked, nodes that are close to each other are merged.

Horizontal Merge Distance

Nodes that are closer than this distance in a horizontal direction are merged into one. This option is only relevant if the Merge Nodes option is checked.

Vertical Merge Distance

Nodes that are closer than this distance in a vertical direction are merged into one. This option is only relevant if the Merge Nodes option is checked.

Resolve Conflicting Shapes

When checked, the tool collapses all street segments that cause street shape conflicts. This is run iteratively until no conflicts exist.

Note:

Segments with the smallest minimal adjacent node valence are collapsed first; that is, this segment valence determines the order of the segment collapse iteration.

Note:

This tool operates planar in the x-z plane. The y-coordinate is ignored. Running this tool on graph networks containing segments on different y-levels is not recommended.

Examples

Simple intersections

Overlapping segments
Intersect segment settings
Intersection of segments

Snap nodes to segments

Segments before snapping
Snap nodes to segments settings
Segments snapped

Simple merge

Segments before merge
Merge node settings
Segments merged

Full cleanup

Segments before cleanup
Full cleanup settings
Segments after cleanup

Resolve conflicting shapes

Shapes before conflict resolved
Resolve conflicting shapes settings
Shapes after conflict resolved


In this topic
  1. Cleanup options
  2. Examples