The dm_control.viewer library can be used to visualize and interact with a control environment. The following example shows how to launch the viewer with an environment from the Control Suite:

from dm_control import suite
from dm_control import viewer

# Load an environment from the Control Suite.
env = suite.load(domain_name="humanoid", task_name="stand")

# Launch the viewer application.
viewer.launch(env)

For convenience we also provide a viewer launch script for the Control Suite in dm_control/suite/explore.py.

The viewer is also capable of running the environment with a policy in the loop to provide actions. This is done by passing the optional policy argument to viewer.launch. The policy should be a callable that accepts a TimeStep and returns a numpy array of actions conforming to environment.action_spec(). The example below shows how to execute a random uniform policy using the viewer:

from dm_control import suite
from dm_control import viewer
import numpy as np

env = suite.load(domain_name="humanoid", task_name="stand")
action_spec = env.action_spec()

# Define a uniform random policy.
def random_policy(time_step):
  del time_step  # Unused.
  return np.random.uniform(low=action_spec.minimum,
                           high=action_spec.maximum,
                           size=action_spec.shape)

# Launch the viewer application.
viewer.launch(env, policy=random_policy)

The viewer contains a built in help screen that can be brought up by pressing F1. You will find a comprehensive description of keyboard and mouse controls there.

Displays status of the simulation:

• State - Current status of the Runtime state machine.
• Time - Simulation clock accompanied by the current setting of time multiplier.
• CPU - How much time per frame does physics simulation consume.
• FPS - How many frames per second is the application rendering.
• Camera - Name of the active camera.
• Paused - Is the simulation paused?
• Error - Recently caught error message.