Introduction
Tracking modes
ArUco markers and marker-based tracking features
- ArUco markers
- Marker-based tracking features
Marker-Based Location Sharing setup
LBE Mode/LBE Hybrid Mode setup
LBE map configuration
Marker-Based Drift Prevention setup
- Setting up Marker-Based Drift Prevention
- Creating ArUco markers for Marker-Based Drift Prevention
Marker-Based Advanced Relocation setup
- Setting up Marker-Based Advanced Relocation
- Creating ArUco markers for Marker-Based Advanced Relocation
Marker-Based Scene Alignment setup
Simulator VR Mode setup
Other services
Additional features
Contact Us

Aligning VR and anchor coordinate systems using an ArUco marker

Use an ArUco marker to align the VR and anchor coordinate systems of your VR simulator.

Note:

Marker-Based Location Sharing must be set up to use this feature. For details, see Marker-Based Location Sharing setup.
Test the APIs before operating your VR simulator to make sure the coordinate systems work as expected.

Define the offset of the VR and anchor coordinate systems.

The offset must be defined before the VR and anchor coordinate systems can be aligned. Use the string key ClearRecenterXform to define the offset:

Controller

string key = "‍ClearRecenterXform"‍;
Interop.WVR_SetParameters
(WVR_DeviceType.WVR_DeviceType_HMD, Marshal.StringToHGlobalAnsi(key));
Interop.WVR_SetParameters
(WVR_DeviceType.WVR_DeviceType_Controller_Right, Marshal.StringToHGlobalAnsi(key));
Interop.WVR_SetParameters
(WVR_DeviceType.WVR_DeviceType_Controller_Left, Marshal.StringToHGlobalAnsi(key));

Wrist tracker

string key = "‍ClearRecenterXform"‍;
Interop.WVR_SetParameters(WVR_DeviceType.WVR_DeviceType_HMD, Marshal.StringToHGlobalAnsi(key));
key = "‍ClearRecenterXformTR"‍;
Interop.WVR_SetParameters(WVR_DeviceType.WVR_DeviceType_HMD, Marshal.StringToHGlobalAnsi(key));

Configure the string key used to align the VR and anchor coordinate systems.
The string key PLAYER01InCarOrg is used to align the VR and anchor coordinate systems. Configure this string key by using the parameters of your ArUco markers.

In the following illustration, the anchor coordinate system is based on the position and orientation of the ArUco markers, following the left-hand rule.

Modify PLAYER01InCarOrg using the values marker position, marker orientation, marker ID, and marker size.

AIO

string key = "‍PLAYER00InCarOrg=0.0,0.0,0.0,0.0,0.0,0.0,1.0,1,0.2"‍;// Tx, Ty, Tz, qx, qy, qz, qw, marker id, marker size
uint RETURN_SIZE = 256;
IntPtr value = Marshal.AllocHGlobal(new IntPtr(RETURN_SIZE));
Interop.WVR_GetParameters(WVR_DeviceType.WVR_DeviceType_HMD, Marshal.StringToHGlobalAnsi(key), value, RETURN_SIZE);
string polling_value = Marshal.PtrToStringAnsi(value);
Marshal.FreeCoTaskMem(value);
if(string.Compare(polling_value, "‍InitMAErr"‍) == 0) // initialization failed, should check config string
{
// write your error handling code here
}

PC VR

string key = "‍PLAYER00InCarOrg="‍;
string setting = "‍-0.4,0.9,-0.4,0.0,0.0,0.0,1.0,1,0.2"‍; // Tx,Ty,Tz,qx,qy,qz,qw,id,size
key += setting;
string result = SendRequestMessage(DeviceType.HMD, key);
if (string.Compare(result, "‍InitMAErr"‍) == 0)
{
   // write your error handling code here
}

Scan the marker.

AIO

// Start
string key = "‍PLAYER00StartScan"‍;
uint RETURN_SIZE = 256;
IntPtr value = Marshal.AllocHGlobal(new IntPtr(RETURN_SIZE));
Interop.WVR_GetParameters(WVR_DeviceType.WVR_DeviceType_HMD, Marshal.StringToHGlobalAnsi(key), value, RETURN_SIZE);
Marshal.FreeCoTaskMem(value);
// Stop
string key = "‍PLAYER00StopScan"‍;
uint RETURN_SIZE = 256;
IntPtr value = Marshal.AllocHGlobal(new IntPtr(RETURN_SIZE));
Interop.WVR_GetParameters(WVR_DeviceType.WVR_DeviceType_HMD, Marshal.StringToHGlobalAnsi(key), value, RETURN_SIZE);
Marshal.FreeCoTaskMem(value);

PC VR

// Start
string key = "‍PLAYER00StartScan"‍;
SendRequestMessage(DeviceType.HMD, key);

// Stop
string key = "‍PLAYER00StopScan"‍;
SendRequestMessage(DeviceType.HMD, key);

Optional: Check the scan status.

AIO

// Check scan
string key = "‍PLAYER00CheckMA"‍;
uint RETURN_SIZE = 256;
  IntPtr value = Marshal.AllocHGlobal(new IntPtr(RETURN_SIZE));
              Interop.WVR_GetParameters(WVR_DeviceType.WVR_DeviceType_HMD, Marshal.StringToHGlobaltrToStringAnsi(value);
Ansi(key), value, RETURN_SIZE);
string polling_value = Marshal.PtrToStringAnsi(value);
Marshal.FreeCoTaskMem(value);
if (string.Compare(polling_value, "‍CTdone"‍) == 0)  // 2 markers scanned
{
//handling with 2nd marker scanned
} 
else if (string.Compare(polling_value, "‍CTpass"‍) == 0)  // 1 marker scanned
{
//handling with first marker scanned
}

PC VR

string key = "‍PLAYER00CheckMA"‍;
string result = SendRequestMessage(DeviceType.HMD, key);
if (string.Compare(result, "‍CTdone"‍) == 0)
{
   // handling with the second marker scanned
}
else if (string.Compare(result, "‍CTpass"‍) == 0)
{
   // handling with the first marker scanned
}

Optional: Compensate for mechanical vibration using a low-pass filter.

You can use the string key PLAYER01PUM_HW_LPF_LEVEL to minimize mechanical vibration. Specify a filter level between 0 and 2. Adjust the filter level according to your needs.

AIO

string key = "‍PLAYER01PUM_HW_LPF_LEVEL=2"‍;
Interop.WVR_SetParameters(WVR_DeviceType.WVR_DeviceType_HMD, Marshal.StringToHGlobalAnsi(key));

PC VR

string key = "‍ PLAYER01PUM_HW_LPF_LEVEL="‍;
string setting = "‍2"‍;
key += setting;
string result = SendRequestMessage(DeviceType.Controller_Left, key);

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