dair_pll.vis_utils

Utility functions for visualizing trajectories.

Visualization of Drake systems can be done with Drake’s VideoWriter. This allows for a relatively thin implementation of visualization for very complex geometries.

The main contents of this file are as follows:

  • A method to generate a dummy DrakeSystem which simultaneously visualizes two trajectories of the same system.

  • A method which takes a DrakeSystem and corresponding trajectory, captures a visualization video, and outputs it as a numpy ndarray.

dair_pll.vis_utils.generate_visualization_system(base_system, visualization_file, learned_system=None, base_system_color=Rgba(r=0.6, g=0.0, b=0.0, a=0.5), learned_system_color=Rgba(r=0.0, g=0.0, b=0.6, a=0.7))[source]

Generate a dummy DrakeSystem for visualizing comparisons between two trajectories of base_system.

Does so by generating a new DrakeSystem in which every model in the base system has a copy. Each illustration geometry element in these two copies is uniformly colored to be visually distinguishable.

The copy of the base system can optionally be rendered in its learned geometry.

Parameters:

  • base_system (DrakeSystem) – System to be visualized.

  • visualization_file (str) – Output GIF filename for trajectory video.

  • learned_system (Optional[DrakeSystem]) – Optionally, the learned system so the predicted trajectory is rendered with the learned geometry.

  • base_system_color (Rgba) – Color to repaint every thing in base system.

  • learned_system_color (Rgba) – Color to repaint every thing in duplicated system.

Return type:

DrakeSystem

Returns:

New DrakeSystem with doubled state and repainted elements.

dair_pll.vis_utils.visualize_trajectory(drake_system, x_trajectory, framerate=30)[source]

Visualizes trajectory of system.

Specifies a framerate for output video, though should be noted that this framerate is only approximately represented by homogeneous integer downsampling of the state trajectory. For example, if drake_system.dt == 1/60 and framerate == 11, the true video framerate will be:

max(round(60/11), 1) == 5.
Parameters:

  • drake_system (DrakeSystem) – System associated with provided trajectory.

  • x_trajectory (Tensor) – (T, drake_system.space.n_x) state trajectory.

  • framerate (int) – desired frames per second of output video.

Return type:

Tuple[ndarray, int]

Returns:

(1, T, 3, H, W) ndarray video capture of trajectory with resolution H x W, which are set to 480x640 in dair_pll.drake_utils. The true framerate, rounded to an integer.