Lane connection model
A drawtonomy Lane has more than two boundaries and a centerline; it also carries four connection slots — Next, Previous, Left, and Right — that link it into a road network.
The four slots
Section titled “The four slots”| Slot | Meaning |
|---|---|
| Next | The lane that traffic on this lane flows into. |
| Previous | The lane that flows into this lane. |
| Left | The lane immediately to the left, sharing a boundary. |
| Right | The lane immediately to the right, sharing a boundary. |
Connections are bidirectional: setting Lane A’s Next to B also sets B’s Previous to A. The editor maintains this invariant for you.
What connections enable
Section titled “What connections enable”Coordinated editing
Section titled “Coordinated editing”When two lanes share a boundary — because they are Left/Right neighbours, or because Next/Previous lanes meet end-to-end — that boundary is a single object. Drag a point on it and both lanes update.
The topology already says what is glued to what, so geometry doesn’t need to be repaired by hand each time you tweak a lane.
Coherent export
Section titled “Coherent export”Both OpenDRIVE and Lanelet2 encode lane connectivity. drawtonomy’s exporters use the connection slots directly, with no inference or heuristics that would fall over on edge cases. A scene that looks right in the editor exports as a real road network rather than a bag of polylines.
Round-trip with imports
Section titled “Round-trip with imports”The Lanelet2 importer reads the same connection model from .osm
files. You can edit a Lanelet2 map in drawtonomy and export it
back without losing topology.
When connections are inferred
Section titled “When connections are inferred”drawtonomy sets connections automatically when the intent is clear:
- Drawing a lane that starts on an existing lane’s endpoint sets Previous.
- The parallel-lane shortcut (Alt+click with the Lane tool) sets Left or Right.
- Placing an intersection template wires up every approach lane.
- The Lane Generator infers connections from OSM topology where unambiguous.
For everything else, set them by hand in the Attribute Panel — see Manage lane connections.
What connections do not encode
Section titled “What connections do not encode”- Direction of travel is implied by Next/Previous, but not encoded separately. Bidirectional roads are modelled as two opposing lanes with their own Next/Previous chains.
- Turn restrictions at intersections aren’t modelled in drawtonomy itself. They appear in the OpenDRIVE/OpenSCENARIO export through the intersection template that produced them.
- Speed limits, surface type, lighting — none of these. drawtonomy is geometry plus topology; semantic attributes are out of scope.
See also
Section titled “See also”- Manage lane connections — the editor steps.
- drawtonomy.svg format — how connections are persisted on save.