Data Export: CSV

CSV Export

Captured tracking data can be exported in Comma Separated Values (CSV) format. This file format uses comma delimiters to separate multiple values in each row, and it can be imported by spreadsheet software or a programming script. Depending on which data export options are enabled, exported CSV files can contain marker data, Rigid Body data, and/or Skeleton data. CSV export options are listed in the following charts:

General Export Options

CSV Export Options

Physical Markers vs Marker Constraints During Occlusion

Rigid Body markers, trained markerset markers or Skeleton bone markers are referred to as Marker Constraints. They appear as transparent spheres within a Rigid Body, or a Skeleton, and each sphere reflect the position that a Rigid Body, or a Skeleton, expects to find a 3D marker. When the asset definitions are created, it is assumed that the markers are fixed at the same location and do not move over the course of capture.

In the CSV file, Rigid Body markers have a physical marker column and a Marker Constraints column. They have nearly the same ID but are distinguished by the first 8 characters as uniquely identifiable.

When a marker is occluded in Motive, the Marker Constraints will display the last known position of where it thinks the marker should be in the CSV file. The actual physical marker will display a blank cell or null value since Motive cannot account for its actual location due to its occlusion.

CSV Header

When the header is disabled, this information will be excluded from the CSV files. Instead, the file will have frame IDs in the first column, time data on the second column, and the corresponding mocap data in the remaining columns.

CSV Headers

TIP: Occlusion in the marker data

When there is an occlusion of a marker, the CSV file will contain blank cells. This can interfere when running a script to process the CSV data. It is recommended to optimize the system setup to reduce occlusions. To omit unnecessary frame ranges with frequent marker occlusions, select the frame range with the most complete tracking results. Another solution to this is to use Fill Gaps to interpolate missing trajectories in post-processing.

Force Plate Data / Analog Data

For Takes containing force plates (AMTI or Bertec) or data acquisition (NI-DAQ) devices, additional CSV files will be exported for each connected device. For example, if you have two force plates and a NI-DAQ device in the setup, a total 4 CSV files will be created when you export the tracking data from Motive. Each of the exported CSV files will contain basic properties and settings at its header, including device information and sample counts. Also, mocap frame rate to device sampling rate ratio is included since force plate and analog data are sampled at higher sampling rates.

Since device data is usually sampled at a higher rate than the camera system, the camera samples are collected at the center of the corresponding device data samples that were collected. For example, if the device data has 9 sub-frames for each camera frame sample, the camera tracking data will be recorded at every 5th frame of device data.

  • Force Plate Data: Each of the force plate CSV files will contain basic properties such as platform dimensions and mechanical-to-electrical center offset values. The mocap frame number, force plate sample number, forces (Fx/Fy/Fz), moments (Mx, My, Mz), and location of the center of pressure (Cx, Cy, Cz) will be listed below the header.

  • Analog Data: Each of the analog data CSV files contains analog voltages from each configured channel.

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