How to use realtime factor

It is possible to modify the speed of simulation (the speed of time published on the /clock topic is not affected):

• from the start of the simulation (using parameter),
• during the simulation (using the GUI slider).

Use parameter

• When you run simulations on the command line, add an global_real_time_factor parameter with a custom value (the default is 1.0).

ros2 launch scenario_test_runner scenario_test_runner.launch.py \
architecture_type:=awf/universe/20250130 \
record:=false \
scenario:='$(find-pkg-share scenario_test_runner)/scenario/sample.yaml' \
sensor_model:=sample_sensor_kit \
vehicle_model:=sample_vehicle \
global_real_time_factor:="0.5"

• The smaller the value you specify, the slower the simulation will progress.

Use slider on run time

• When the simulation is started you can add the RViz panel by clicking Panels -> Add new panel in the top left corner of RViz.

• Then in the pop up window please select RealTimeFactorSliderPanel and double click on it.

• Slider controlling the speed of simulation time should be visible on the left side of the screen.

• The process of adding the panel is also visible in the video:

Configure use_sim_time parameter

Parameter use_sim_time of openscenario_interpreter is false by default and can be modified by passing it using command line.

ros2 launch scenario_test_runner scenario_test_runner.launch.py \
architecture_type:=awf/universe/20250130 \
record:=false \
scenario:='$(find-pkg-share scenario_test_runner)/scenario/sample.yaml' \
sensor_model:=sample_sensor_kit \
vehicle_model:=sample_vehicle \
global_real_time_factor:="0.5" \
use_sim_time:=true

However, this impacts the time published on the /clock topic and the time used by Autoware. Details are shown in the table below:

use_sim_time launch parameter	/clock time published by scenario_simulator_v2	AWF Autoware Time
false (default)	walltime	walltime from /clock
true	simulation	simulation from /clock

Below are also some bullet points explaining the impact of the use_sim_time parameter on scenario_simulator_v2 and Autoware:

• use_sim_time:=True passed using command line
  • Both Autoware and scenario_simulator_v2 are launched with use_sim_time=true.
  • Time published on /clock is the simulation time (starting from 0).
  • Time published on /clock can be controlled by RViz plugin.
  • Simulation time can be controlled by RViz plugin.
• use_sim_time:=False passed using command line (default value)
  • Both Autoware and scenario_simulator_v2 are launched with use_sim_time=false.
  • Time published on /clock is the walltime.
  • Time published on /clock cannot be controlled by RViz plugin.
  • Simulation time can be controlled by RViz plugin.