Virtual Reality

Virtual Reality (VR) is a broad term. In this documentation we are mainly interested in the head mounted displays (HMD) such as Valve Index and Oculus Rift S.

VR and racing games are a great combination. They greatly increase your ability to keep track of your surroundings. Need to make sure no cars is to your left? Simply turn you head and look out the window! With the added depth perception it becomes easier to gauge distances and speeds. But it is not without problems.

When combined with a motion system the largest problem is tracking. Since the motion system applies motion to your head this motion is tracked by the VR headset. It becomes very apparent during braking when your face is moved closer to the steering wheel by the motion system’s pitch. However, SIMRIG Control Center is equipped with motion cancellation to combat this issue.

Motion Cancellation

Motion cancellation can counteract the motion system’s impact on the VR-headset. Essentially subtracting the rig’s motion from your own. Allowing the motion system to move your body without affecting the tracked position.

This works by computing the difference between where your head is due to motion caused by the motion system and where it should have been if you were stationary. This difference is applied to the VR-headset’s tracked position (negating the motion system’s impact on the VR-headset’s tracking.)

Prerequisites

Note

Motion cancellation is available for SteamVR only. However, you can use Oculus Rift and Oculus Rift S together with SteamVR. Read more about SteamVR + Oculus.

Warning

Uninstall all other motion cancellation solutions for SteamVR such as OpenVR-InputEmulator prior to installing SIMRIG Motion Cancellation.

You will need to following:

  1. A VR-headset such as Valve Index or Oculus Rift S

  2. SteamVR

  3. SIMRIG Control Center version 1.20.0 or higher

  4. SIMRIG SR1 firmware version 17 or higher

  5. SIMRIG Motion Cancellation – the optional motion cancellation component for SIMRIG Control Center

  6. Proper configuration values for motion cancellation

If these prerequisites are met you should be able to access the VR-page in SIMRIG Control Center. Motion cancellation is an optional component of SIMRIG Control Center. It is not installed by default. You are prompted to install SIMRIG Motion Cancellation when you open the VR-page for the first time.

_images/mc-not-installed.png

You are prompted to install SIMRIG Motion Cancellation when you open the VR-page for the first time.

Reference tracker

Motion cancellation requires a reference. This can either be the position sensors in the SIMRIG actuators or a physical device mounted to the rig (such as a Vive Tracker or spare controller.)

_images/mc-reference.png

There are multiple reference modes to choose from:

Software

The Software tracker relies on the actuators’ position sensors and the Rig geometry settings. No extra hardware required. Make sure to use accurate measurments.

Vive Tracker

This mode requires a Vive Tracker to be mounted on your rig. Mount the tracker close to your head for best performance.

Controller

This mode requires that a hand controller is mounted on your rig. Mount the controller close to your head for best performance.

Note

The system will fall back to Software mode if your reference tracker is unavailable.

Rig geometry

The rig geometry is required to compute the motion system’s position in VR coordinates. You must verify these values using a tape ruler.

_images/mc-rig-geometry.png
Ear to floor

While sitting in your rig, measure the vertical distance from your ears to the ground.

Ear to rear

While sitting in your rig, measure the horizontal distance from your ears to the center of the rear actuators. Enter a positive number if your ears are in-front of the rear actuator (in-between the rear and the front actuators.) Enter zero if you ears are directly above the rear actuators.

Width

Enter the center-to-center distance between the rear actuators.

Length

Enter the center-to-center distance between the left actuators.

Status messages

The VR-page contains a status messages that describes the status of SIMRIG Motion Cancellation. This message can be useful when trying to determine if the system is working as intended or not.

_images/mc-status.png

An example status message. This is shown when SteamVR isn’t running.

Common status messages:

  • Not loaded – the motion cancellation component is installed on your system but not yet loaded; enable motion cancellation to continue

  • Connected to SteamVR – everything is nominal; motion cancellation is working as expected

  • SteamVR not running – SteamVR is not running on your PC; this message should go away when you start SteamVR (it can take up to 30 seconds to detect SteamVR)

  • SteamVR not initialized – SteamVR is not yet initialized; please wait

Other status messages:

  • Ready – the motion cancellation component is loaded and ready to proceed; please wait

  • No HMD detected – your head mounted display has not yet been detected; please make sure the display is powered on and recognized by SteamVR

  • SteamVR not installed – SteamVR is not installed on your PC; please install SteamVR

  • Driver not installed – the SIMRIG Motion Cancellation driver is not detected; please reinstall SIMRIG Motion Cancellation

  • Incorrect SteamVR version – either SteamVR is not installed on your PC or your SteamVR installation is outdated; however, if your are reading this in the future, it could also be that SteamVR has released a new version that is no longer backwards compatible with SIMRIG Motion Cancellation

  • SteamVR error – SteamVR encountered an unforeseen error; see the log for details and please contact support if the problem persists

  • Unknown hardware position – the SIMRIG SR1 is not reporting its current position; please upgrade your firmware to version 17 or above

  • Failed to load plugin – SIMRIG Motion Cancellation is out of date or corrupt; please reinstall SIMRIG Motion Cancellation