Spawning vehicles

[EhsanSabouni]

Hi

I want to use ramp in MARL. But I do not know how to spawn car on side road (in ramp). Does anyone know how to spawn car in an arbitrary position?

I checked the website and found this but I am not sure how to find these values including navigation module, spawn_lane_index and so on.

    # A BaseNavigation instance. It should match the road network type.
    navigation_module=None,
    # A lane id specifies which lane to spawn this vehicle
    spawn_lane_index=None,
    # destination lane id. Required only when navigation module is not None.
    destination=None,
    # the longitudinal and lateral position on the spawn lane
    spawn_longitude=5.0,
    spawn_lateral=0.0,

Thanks

[QuanyiLi]

Hi @EhsanSabouni,

All lanes will have its corresponding ID, which can be retrieved by lane.id. And you can find all lanes from env.engine.current_map.road_network which also records the connectivity information for all lanes. Usually speaking, the lane id is generated following some rules. This line is for creating the merging lane:

metadrive/metadrive/component/pgblock/ramp.py

Line 139 in 05ec6c8

self.add_respawn_roads(straight_road)

Checking the properties of 'straight_road' would tell you the lane ID in style (node1, node2, lane_index). If you are connecting multiple ramps, the ID of this merging lane only differs at the first digit which indicates the block order.