bbi.scenarios

class Scenario(world: BaseWorld, num_frames: int, total_seconds: float)

Bases: object

Defines a scenario, a collection of sequenced states.

Warning

A scenario should never be created directly. Use World.new_scenario() instead.

Parameters:

  • num_frames (int) – The number of frames in the scenario.

  • total_seconds (float) – The expected total duration of this scenario in seconds. This is used together with num_frames to calculate the delta time between frames. For example, if num_frames is 100 and total_seconds is 10, then the delta time between frames is 0.1 seconds. Set it to 0.0 to disable delta time calculation.

set_keyframe(instance: Animatable, frame_id: int, **kwargs) → None

Update the attributes of an Animatable instance at a specific frame.

Parameters:

  • instance (Animatable) – Target Animatable instance to set the updates.

  • frame_id (int) – The frame number (0-indexed) at which to set the updates.

  • **kwargs – The Animatable’s attribute to update.

clear_keyframes(instance: Animatable) → None

Clear the keyframes of an Animatable instance.

Parameters:

instance (Animatable) – The Animatable instance to clear the keyframes.

goto(frame_id: int)

Jumps to a specific frame id (0-indexed).

Useful when debugging camera or object positions.

Parameters:

frame_id (int) – The frame number to jump to.

preview_animation(start_frame: int = 0, end_frame: int | None = None)

Previews the animation by visualizing each frame in the scenario.

The viewport will be updated to show the requested frames. The assets will not return to their original positions after the preview.

Parameters:

  • start_frame (int, optional) – The starting frame number (0-indexed) to preview. Defaults to 0.

  • end_frame (int | None, optional) – The ending frame number (inclusive) to preview. If None, the scenario will be previewed until the last frame. Defaults to None.

render(params: RenderParams = RgbWithLabels(), start_frame: int = 0, warmup_frames: int | None = None, end_frame: int | None = None)

Dispatches the render call to the renderer.

For each frame in num_frames, the scene state is traversed. Each Node is executed, i.e. SpawnZones instantiate objects in geometry, and animation states are updated. Finally, the scene is drawn.

Parameters:

  • params (RenderParams, optional) – The parameters to use for the render. The different subclasses of RenderParams result in different render outputs, where the valid subclasses are: Rgb, RgbWithLabels. This defaults to RgbWithLabels(), i.e. this will generate labelled RGB images using default settings. See each subclass’s documentation for the full set of parameters that can be passed.

  • start_frame (int, optional) – The starting frame number (0-indexed) to render. Defaults to 0.

  • warmup_frames (int, optional) – The number of warmup frames before the render is captured. Defaults to None and will be determined by the weather and other scene variables.

  • end_frame (int, optional) – The ending frame number (inclusive) to render. If None, the scenario will be rendered until the last frame. Defaults to None.