Set the floor plane
- Adaptavist ScriptRunner for Confluence Cloud (Unlicensed)
The final stage in calibrating your Vicon cameras is to set the floor plane, using markers in the volume to automatically define it.
The position of the virtual floor that is derived during setting the origin is extrapolated from the position of the wand in relation to floor of the volume. As the wand is a small object compared with the size of the volume, any slight discrepancy from the wand being level has a large effect over the rest of the volume when you set the origin. To account for any discrepancy, you set a floor plane, which takes a much larger area into account, so that the virtual floor lines up correctly with the actual floor plane.
To set the floor plane:
Ensure you have completed the rest of the camera calibration procedure and set the origin (see Set the volume origin).
Turn off the calibration object or remove it from the volume.
Place a minimum of four 14 mm Vicon markers across the floor of your capture volume.
(If you are not using 14 mm markers or have changed the default 7 mm floor plane setting, see Adjust the Set Floor Plane settings.)
On the Camera Calibration tab, go to the Volume Setup section, ensure the advanced options are displayed and click Start Set Floor Plane.
After a few seconds, click Set Floor Plane.
In the 3D View, display the View Filters and in the Volume options, ensure that Cameras is selected.
In the Perspective view, note that the cameras shift as a group slightly along one or more rotation axes to better reflect an average of the markers scattered across the floor, taking into account any offsets that you specified.
In C:\ProgramData\Vicon\Calibrations, the LatestCalibration.xcp file is updated. This file is automatically used for every subsequent capture.
Tip: To more accurately visualize the size of your volume in Shogun Live, you can change the size and shape of the floor grid. To do this, in the Camera Calibration panel, go to the Volume Setup section, ensure the advanced options are displayed and under Set Floor Grid, change the values (in mm) to give the required result.
Your Vicon cameras are now calibrated and ready to capture data.
Adjust the Set Floor Plane settings
If you are not using 14 mm markers, to enable you to set the floor plane accurately, select Advanced parameters , then select the ellipsis next to Start Set Floor Plane, and change the Height offset value to an appropriate value. The Height offset is the amount (in mm) by which to adjust the floor plane (the default is 7 mm). Because Shogun finds the centers of the markers, set a Height offset that accounts for the size of the markers (for example, for 14 mm markers, the Height offset is 7 mm). If the markers include a base, take this into account in your calculations.