Difference between revisions of "Data Export: C3D"

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(C3D Export)
 
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  [[OptiTrack Documentation Wiki|Back to the Main Page]] → [[Motive Documentation|Back to Motive Documentation]] → [[Data Export|Back to Data Export]]
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  [[Main Page]] → [[Motive Documentation]] → [[Data Export]] → [[Data Export: C3D]]
 
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__NOTOC__
 
=C3D Export=
 
=C3D Export=
 
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Tracking data can be exported into the C3D file format. C3D (Coordinate 3D) is a binary file format that is widely used especially in biomechanics and motion study applications. Recorded data from external devices, such as force plates and NI-DAQ devices, will be recorded within exported C3D files. Note that common biomechanics applications use a Z-up right-hand coordinate system, whereas Motive uses a Y-up right-hand coordinate system. More details on coordinate systems are described in the later section. Find more about C3D files from https://www.c3d.org/.
 
Tracking data can be exported into the C3D file format. C3D (Coordinate 3D) is a binary file format that is widely used especially in biomechanics and motion study applications. Recorded data from external devices, such as force plates and NI-DAQ devices, will be recorded within exported C3D files. Note that common biomechanics applications use a Z-up right-hand coordinate system, whereas Motive uses a Y-up right-hand coordinate system. More details on coordinate systems are described in the later section. Find more about C3D files from https://www.c3d.org/.
  
 
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{|class="wikitable" style="color:black; margin: auto; width:85%;"
{|class="wikitable" style="color:black; margin: auto; width:75%;"
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|+C3D Export Options
 
|+C3D Export Options
 
!style ="width:25%"|Options
 
!style ="width:25%"|Options
 
!Descriptions
 
!Descriptions
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|-
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|style="padding: 10px;"|Frame Rate
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|style="padding: 10px;"|Number of samples included per every second of exported data.
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|-
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|style="padding: 10px;"|Start Frame
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|style="padding: 10px;"|Start frame of the exported data. You can either set it to the recorded first frame of the exported ''Take'' or to the start of the working range, or scope range, as configured under the [[Control Deck]] or in the [[Graph View pane]].
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|-
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|style="padding: 10px;"|End Frame
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|style="padding: 10px;"|End frame of the exported data. You can either set it to the recorded end frame of the exported ''Take'' or to the end of the working range, or scope range, as configured under the [[Control Deck]] of in the [[Graph View pane]].
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|-
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|style="padding: 10px;"|Use Zero Based Frame Index
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|style="padding: 10px;"|C3D specification defines first frame as index 1. Some applications import C3D files with first frame starting at index 0. Setting this option to true will add a start frame parameter with value zero in the data header.
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|-
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|style="padding: 10px;"|Export Unlabeled Markers
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|style="padding: 10px;"|Includes unlabeled marker data in the exported C3D file. When set to False, the file will contain data for only labeled markers.
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|-
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|style="padding: 10px;"|Export Finger Tip Markers
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|style="padding: 10px;"|Includes virtual reconstructions at the finger tips. Available only with skeletons that support finger tracking (e.g. Baseline + 11 Additional Markers + Fingers (54))
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|-
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|style="padding: 10px;"|Use Timecode
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|style="padding: 10px;"|Includes timecode.
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|-
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|style="padding: 10px;"|Rename Unlabeled As _000X
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|style="padding: 10px;"|Unlabeled markers will have incrementing labels with numbers _000#.
 
|-
 
|-
 
|style="padding: 10px;"|Units
 
|style="padding: 10px;"|Units
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(Exported unit maybe rescaled to a standard unit when imported into another software.)
 
(Exported unit maybe rescaled to a standard unit when imported into another software.)
 
|-
 
|-
|style="padding: 10px;"|Exported Unlabeled Marker
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|style="padding: 10px;"|Axis Convention
|style="padding: 10px;"|Includes unlabeled marker data in the exported C3D file. When set to False, the file will contain data for only labeled markers.
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|style="padding: 10px;"|Sets the axis convention on exported data. This can be set to a custom convention, or preset convetions for exporting to Motion Builder or Visual3D/Motion Monitor.
|-
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|style="padding: 10px;"|Exported Frame Indices Start at Zero
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|style="padding: 10px;"|C3D specification defines first frame as index 1. Some applications import C3D files with first frame starting at index 0. Setting this option to true will add a start frame parameter with value zero in the data header.
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|-
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|style="padding: 10px;"|Axis
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|style="padding: 10px;"|Can be set either in custom setting or in MotionBuilder Compatible axes convention. Read below for more information.
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|-
 
|-
 
|style="padding: 10px;"|X Axis
 
|style="padding: 10px;"|X Axis
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|style="padding: 10px;"|Z Axis
 
|style="padding: 10px;"|Z Axis
 
|-
 
|-
|style="padding: 10px;"|Rename Unlabeled As _000X
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|style="padding: 10px;"|Scale
|style="padding: 10px;"|Unlabeled markers will have incrementing labels with numbers _000#.
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|style="padding: 10px;"|Apply scaling to the exported tracking data.
 
|-
 
|-
|style="padding: 10px;"|Use Timecode
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|style="padding: 10px;"|Marker Name Syntax.
|style="padding: 10px;"|Includes timecode.
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|style="padding: 10px;"|Choose whether the marker naming syntax usese ":" or "_" as the name separator. The name separator will be used to separate the asset name and the corresponding marker name in the exported data (e.g. AssetName:MarkerLabel or AssetName_MarkerLabel or MarkerLabel).
|-
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|style="padding: 10px;"|Marker Name Separator.
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|style="padding: 10px;"|Choose ":" or "_" for marker name separator. The name separator will be used to separate the asset name and the corresponding marker name in the exported data (e.g. AssetName:MarkerLabel or AssetName_MarkerLabel).
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|}
 
|}
  
 
<div class="padded">
 
 
==C3D Axes==
 
==C3D Axes==
Since Motive uses a different coordinate system from the system used in common biomechanics applications, it is necessary to modify the coordinate axis to a compatible convention in the C3D export settings. When exporting to
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<div class="padded">
biomechanics analysis applications using z-up right-handed convention (e.g. Visual3D), the following changes on the axes should be made under the custom axis settings.
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====Common Conventions====
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<div class="padded">
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[[Image:Biomech C3DExport_20.png|thumb|500 px|C3D export setting for applications using z-up right-handed coordinate systems.]]
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Since Motive uses a different coordinate system than the system used in common biomechanics applications, it is necessary to modify the coordinate axis to a compatible convention in the C3D exporter settings. For biomechanics applications using z-up right-handed convention (e.g. Visual3D), the following changes must be made under the custom axis.
  
 
* X axis in Motive should be configured to positive X
 
* X axis in Motive should be configured to positive X
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* Z axis in Motive should be configured to positive Y.
 
* Z axis in Motive should be configured to positive Y.
  
Note: For Motive 1.10, Y axis must be converted to positive Z instead, this issue has been fixed on Motive 1.10.1.
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This will convert the coordinate axis of the exported data so that the x-axis represents the anteroposterior axis (left/right), the y-axis represents the mediolateral axis (front/back), and the z-axis represents the longitudinal axis (up/down).
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</div>
  
[[Image:Biomech C3DExport.png|thumb|center|500 px|C3D export setting for applications using z-up right-handed coordinate systems.]]
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====MotionBuilder Compatible Axis Convention====
 
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<div class="padded">
==MotionBuilder Compatible Axis Convention==
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[[Image:Mobu_C3DExport.png|thumb|500 px|C3D export MotionBuilder compatible axis setting]]
This is a convenience option for setting the axes for use in Autodesk MotionBuilder. Even though Motive and MotionBuilder both use the same coordinate system, MotionBuilder assumes biomechanics standards when importing C3D files (negative X axis to positive X axis; positive Z to positive Y; positive Z to positive Y). Accordingly, when exporting C3D files for MotionBuilder use, set the Axis setting to MotionBuilder Compatible, and the axes will be exported using the following convention:
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This is a preset convention for exporting C3D files for use in Autodesk MotionBuilder. Even though Motive and MotionBuilder both use the same coordinate system, MotionBuilder assumes biomechanics standards when importing C3D files (negative X axis to positive X axis; positive Z to positive Y; positive Z to positive Y). Accordingly, when exporting C3D files for MotionBuilder use, set the Axis setting to '''MotionBuilder Compatible''', and the axes will be exported using the following convention:
 
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* Motive: X axis &rarr; Set to negative X &rarr; Mobu: X axis
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* Motive: Y axis &rarr; Set to positive Z &rarr; Mobu: Y axis
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* Motive: Z axis &rarr; Set to positive Y &rarr; Mobu: Z axis
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<center>[[Image:C3D_Axis.png|800 px]]</center>
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* Motive: X axis → Set to negative X → Mobu: X axis
<center>Axis Conversion in C3D Files</center>
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* Motive: Y axis → Set to positive Z → Mobu: Y axis
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* Motive: Z axis → Set to positive Y → Mobu: Z axis
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</div>
 
</div>
 
</div>

Latest revision as of 19:56, 2 May 2019

Main PageMotive DocumentationData ExportData Export: C3D

C3D Export


Tracking data can be exported into the C3D file format. C3D (Coordinate 3D) is a binary file format that is widely used especially in biomechanics and motion study applications. Recorded data from external devices, such as force plates and NI-DAQ devices, will be recorded within exported C3D files. Note that common biomechanics applications use a Z-up right-hand coordinate system, whereas Motive uses a Y-up right-hand coordinate system. More details on coordinate systems are described in the later section. Find more about C3D files from https://www.c3d.org/.

C3D Export Options
Options Descriptions
Frame Rate Number of samples included per every second of exported data.
Start Frame Start frame of the exported data. You can either set it to the recorded first frame of the exported Take or to the start of the working range, or scope range, as configured under the Control Deck or in the Graph View pane.
End Frame End frame of the exported data. You can either set it to the recorded end frame of the exported Take or to the end of the working range, or scope range, as configured under the Control Deck of in the Graph View pane.
Use Zero Based Frame Index C3D specification defines first frame as index 1. Some applications import C3D files with first frame starting at index 0. Setting this option to true will add a start frame parameter with value zero in the data header.
Export Unlabeled Markers Includes unlabeled marker data in the exported C3D file. When set to False, the file will contain data for only labeled markers.
Export Finger Tip Markers Includes virtual reconstructions at the finger tips. Available only with skeletons that support finger tracking (e.g. Baseline + 11 Additional Markers + Fingers (54))
Use Timecode Includes timecode.
Rename Unlabeled As _000X Unlabeled markers will have incrementing labels with numbers _000#.
Units Sets which unit is used in exported data.

(Exported unit maybe rescaled to a standard unit when imported into another software.)

Axis Convention Sets the axis convention on exported data. This can be set to a custom convention, or preset convetions for exporting to Motion Builder or Visual3D/Motion Monitor.
X Axis Allows customization of the axis convention in the exported file by determining which positional data to be included in the corresponding data set.
Y Axis
Z Axis
Scale Apply scaling to the exported tracking data.
Marker Name Syntax. Choose whether the marker naming syntax usese ":" or "_" as the name separator. The name separator will be used to separate the asset name and the corresponding marker name in the exported data (e.g. AssetName:MarkerLabel or AssetName_MarkerLabel or MarkerLabel).

C3D Axes

Common Conventions

C3D export setting for applications using z-up right-handed coordinate systems.

Since Motive uses a different coordinate system than the system used in common biomechanics applications, it is necessary to modify the coordinate axis to a compatible convention in the C3D exporter settings. For biomechanics applications using z-up right-handed convention (e.g. Visual3D), the following changes must be made under the custom axis.

  • X axis in Motive should be configured to positive X
  • Y axis in Motive should be configured to negative Z
  • Z axis in Motive should be configured to positive Y.

This will convert the coordinate axis of the exported data so that the x-axis represents the anteroposterior axis (left/right), the y-axis represents the mediolateral axis (front/back), and the z-axis represents the longitudinal axis (up/down).

MotionBuilder Compatible Axis Convention

C3D export MotionBuilder compatible axis setting

This is a preset convention for exporting C3D files for use in Autodesk MotionBuilder. Even though Motive and MotionBuilder both use the same coordinate system, MotionBuilder assumes biomechanics standards when importing C3D files (negative X axis to positive X axis; positive Z to positive Y; positive Z to positive Y). Accordingly, when exporting C3D files for MotionBuilder use, set the Axis setting to MotionBuilder Compatible, and the axes will be exported using the following convention:

  • Motive: X axis → Set to negative X → Mobu: X axis
  • Motive: Y axis → Set to positive Z → Mobu: Y axis
  • Motive: Z axis → Set to positive Y → Mobu: Z axis