Class that contains time information for simulated data. This information is automatically retrieved as part of the carla.WorldSnapshot the client gets on every frame, but might also be used in many other situations such as a carla.Sensor retrieveing data.
A class that contains every actor present on the scene and provides access to them. The list is automatically created and updated by the server and it can be returned using carla.World.
Filters a list of Actors matching `wildcard_pattern` against their variable **<font color="#f8805a">type_id</font>** (which identifies the blueprint used to spawn them). Matching follows [fnmatch](https://docs.python.org/2/library/fnmatch.html) standard.
The simulation has some advanced configuration options that are contained in this class and can be managed using carla.World and its methods. These allow the user to choose between client-server synchrony/asynchrony, activation of "no rendering mode" and either if the simulation should run with a fixed or variable time-step. Check [this](adv_synchrony_timestep.md) out if you want to learn about it.
States the synchrony between client and server. When set to true, the server will wait for a client tick in order to move forward. It is false by default.
When enabled, the simulation will run no rendering at all. This is mainly used to avoid overhead during heavy traffic simulations. It is false by default.
Ensures that the time elapsed between two steps of the simulation is fixed. Set this to <b>0.0</b> to work with a variable time-step, as happens by default.
Creates an object containing desired settings that could later be applied through carla.World and its method **<font color="#7fb800">apply_settings()</font>**.
Class that defines attachment options between an actor and its parent. When spawning actors, these can be attached to another actor so their position changes accordingly. This is specially useful for cameras and sensors. [Here](ref_code_recipes.md#attach-sensors-recipe) is a brief recipe in which we can see how sensors can be attached to a car when spawned. Note that the attachment type is declared as an enum within the class.
An attachment that expands or retracts depending on camera situation. SpringArms are an Unreal Engine component so [check this out](ref_code_recipes.md#attach-sensors-recipe) to learn some more about them.
World objects are created by the client to have a place for the simulation to happen. The world contains the map we can see, meaning the asset, not the navigation map. Navigation maps are part of the carla.Map class. It also manages the weather and actors present in it. There can only be one world per simulation, but it can be changed anytime.
The ID of the episode associated with this world. Episodes are different sessions of a simulation. These change everytime a world is disabled or reloaded. Keeping track is useful to avoid possible issues.
The content of the world is parsed and printed as a brief report of its current state.
# --------------------------------------
- def_name:apply_settings
return:int
params:
- param_name:world_settings
type:carla.WorldSettings
doc:>
This method applies settings contained in an object to the simulation running and returns the ID of the frame they were implemented.
# --------------------------------------
- def_name:get_actor
return:carla.Actor
params:
- param_name:actor_id
type:int
doc:>
Looks up for an actor by ID and returns <b>None</b> if not found.
# --------------------------------------
- def_name:get_actors
return:carla.ActorList
params:
- param_name:actor_ids
type:list
default:None
doc:>
The IDs of the actors being searched. By default it is set to <b>None</b> and returns every actor on scene.
doc:>
Retrieves a list of carla.Actor elements, either using a list of IDs provided or just listing everyone on stage. If an ID does not correspond with any actor, it will be excluded from the list returned, meaning that both the list of IDs and the list of actors may have different lengths.
Returns the object containing the navigation map used to describe this world.
# --------------------------------------
- def_name:get_random_location_from_navigation
return:carla.Location
doc:>
This can only be used with walkers. It retrieves a random location to be used as a destination using the **<font color="#7fb800">go_to_location()</font>** method in carla.WalkerAIController. This location will be part of a sidewalk. Roads, crosswalks and grass zones are excluded. The method does not take into consideration locations of existing actors so if a collision happens when trying to spawn an actor, it will return an error. Take a look at [`spawn_npc.py`](https://github.com/carla-simulator/carla/blob/e73ad54d182e743b50690ca00f1709b08b16528c/PythonAPI/examples/spawn_npc.py#L179) for an example.
# --------------------------------------
- def_name:get_snapshot
return:carla.WorldSnapshot
doc:>
Returns a snapshot of the world at a certain moment comprising all the information about the actors.
Returns the spectator actor. The spectator is a special type of actor created by Unreal Engine, usually with ID=0, that acts as a camera and controls the view in the simulator window.
The method will start callbacks for a defined function `callback`. It will return the ID for this callback so it can be removed with **<font color="#7fb800">remove_on_tick()</font>**.
Determines how fixed and rigorous should be the changes in position according to its parent object.
doc:>
The method will create, return and spawn an actor into the world. The actor will need an available blueprint to be created and a transform (location and rotation). It can also be attached to a parent with a certain attachment type.
This only has effect on synchronous mode, when both client and server move together. The method tells the server when to step to the next frame and returns the id of the newly started frame.
Helper class part of carla.World that defines methods for creating debug shapes. By default, shapes last one second. They can be permanent, but take into account the resources needed to do so. Check out this [recipe](ref_code_recipes.md#debug-bounding-box-recipe) where the user takes a snapshot of the world and then proceeds to draw bounding boxes for traffic lights.
