Tech Tip: Merging Position and Rotation Trackers in Vizconnect

June 14, 2019

Sado Rabaudi

Vizconnect’s Merged Tracker option combines the data from separate position and orientation trackers into a single 6DOF virtual tracker. The merged tracker can be used to move the viewpoint, an avatar, and other objects.  This option is commonly used to combine PPT position with Oculus or inertia cube orientation.

Vizconnect’s guided wizard will automatically create merged trackers when  you specify separate position and orientation trackers during the head and hand tracking setup. If you’re using the merged tracker for avatar IK or as the link source for other objects you’ll need to add the tracker from the advanced configuration menu.

Follow the steps below to create a merged tracker from the advanced menu.  It uses virtual keyboard and mouse trackers option so everyone can follow along. The same steps apply if you are using physical tracking devices:

  1. From the Tools tab in Vizard, select the Vizconnect option. From the Vizconnect Startup page, select option 3 to go to the Advanced Menu.
  2. From the Trackers tab, press Add a New Tracker to open the tracker options dialog box. Select the keyboard option and then press Apply & Exit.
  3. Press Add a New Tracker, select the Mouse Orientation option and then press Apply & Exit.
  4. Press Add a New Tracker and select the Merged option. Select keyboard for Pos Tracker and mouse_orientation for Ori Tracker. Press Apply & Exit.
  5. Open the Status dialog to view the position and orientation of the merged tracker. Give focus to the graphics window so that Vizard registers the key and mouse events. Notice that WASD key presses change the merged tracker position and mouse movements change its orientation

If you are using a PPT tracking system and you also wish to correct yaw (and role) drift of an orientation sensor, you can use the optical heading option in Vizconnect which merges two PPT markers and one orientation marker.  This can either be setup in PPT studio, or added through vizconnect.

  • Select Trackers- Add a New Tracker- and add a WorldViz PPT Tracker for the left and right side of the PPT eyes
  • Add a Virtual Optical Heading Tracker and choose the orientation tracker, the two PPT trackers and input the distance between the two markers. If the distance value is left at -1 then the distance (which should be static) is computed during runtime. If tracking is poor, providing a distance measurement can help to increase performance.

For additional documentation on vizconnect take a look at the tutorials and reference sections of the Vizard Help.