Motionprint Ergo supports motion capture data via Xsens MVNX files. This article walks you through exporting a valid MVNX file from MVN Analyze Pro, selecting it in the app, and understanding what happens during validation — so you reach the input configuration page ready to process.
1. Before You Start
Make sure the following are in place before continuing.
- Motionprint Ergo installed and activated — if you haven't done this yet, see the Getting Started guide.
- MVN Analyze Pro installed — any recent version that supports MVNX version 4 export. This is standard in current releases.
- A completed Xsens motion capture session — the subject should have performed the work task being assessed. The recording must have been collected with a full sensor setup and a completed calibration in MVN Analyze Pro.
- The session file accessible on your computer — you will need to browse to it from within Motionprint Ergo. The app reads the file directly from disk, so it must remain in its location after you select it.
2. Recording Requirements — What the File Must Contain
Before covering the export steps, it is worth understanding what makes a recording valid. The most common source of errors is not a software misconfiguration — it is a recording that is missing required data, either because of how the session was captured or because of the export settings used. Getting this right once prevents most issues.
Motionprint Ergo requires MVNX version 4. Earlier versions may omit position data or have structural differences that will cause validation to fail. Always set the version to 4 when exporting, and check all data points.
Required file structure
| Requirement | Why it matters |
|---|---|
| T-pose frame | Used by the backend to map body segment orientations. The T-pose frame is included automatically when exporting a properly calibrated session with all data points checked. Without it, validation fails immediately. |
frameRate attribute |
Required to calculate timing-based metrics. Must be present on the subject element. |
| Motion frames with position data | Segment positions are used for spatial calculations across all assessment methods. |
| Motion frames with orientation data | Segment orientations are used for posture angles including trunk bending, twisting, and wrist angles. |
<subject> element |
Top-level structural requirement. Its absence means the file is not a valid MVNX file. |
What to record
The recording should capture the portion of the session where the load handling or lifting task takes place. Before exporting, it is worth doing a rough trim in MVN Analyze Pro to remove significant idle time at the start or end — this reduces the file size and speeds up loading in Motionprint Ergo. You do not need to trim precisely; Motionprint Ergo includes a built-in trim tool on the input configuration page where you can set the exact analysis window. However, recordings that contain only unrelated movement with no lifting or load handling will produce unusable results.
All required data is included automatically when you export from MVN Analyze Pro with MVNX version 4 and all data points checked. The most common cause of missing data is exporting with a limited data selection or using an older format version.
3. Exporting from MVN Analyze Pro
The steps below describe the settings that matter for compatibility with Motionprint Ergo. The exact menu layout in MVN Analyze Pro may vary slightly between versions, but the core export options — format, version, and data selection — are present in all recent releases.
Open your session in MVN Analyze Pro.
Go to File → Export (or the equivalent export option in your version).
Select MVNX as the export format.
Set the MVNX version to 4. This is critical — earlier versions may omit position data or have structural differences that cause validation to fail.
In the data selection panel, check all data points. Do not deselect any data categories — Motionprint Ergo uses position, orientation, joint angle, and landmark data.
Choose a destination folder you can easily navigate to from Motionprint Ergo — for example, a dedicated folder for your ergonomic assessments.
Click Export and wait for the file to finish writing. MVNX files range from a few MB to several hundred MB depending on recording length.
Note the location of the saved .mvnx file — you will browse to it in the next step.
There is no file size limit imposed by Motionprint Ergo, and MVNX files have been tested successfully with recordings up to one hour in length. That said, recording length should reflect a representative work cycle rather than an entire shift — a few minutes of task activity is typically sufficient.
4. Selecting the File in Motionprint Ergo
Once you have a valid MVNX file, the flow inside Motionprint Ergo is straightforward.
In Motionprint Ergo, click Create in the sidebar and select your assessment method.
The Input Source page appears. Click the Xsens MVNX tile to select it as the input source.
A file browser opens. Navigate to the folder where you saved the .mvnx file, select it, and confirm.
A brief Validating and loading file… indicator appears while the app performs a structural check. This typically completes in under a second even for large files.
If validation passes, the app navigates automatically to the Input Configuration page. If it fails, an error message is shown — see the next section for what each message means.
The app stores the file path and reads from it directly — no data is transferred to a server or copied elsewhere. If the file is moved or deleted before you run the analysis, the app will show: "The MVNX file could not be found on your computer. It may have been moved or deleted. Please select the file again."
5. Validation Errors — What They Mean and How to Fix Them
Validation happens in two stages. The first stage is a fast structural check that runs as soon as you select a file — errors here are shown immediately. The second stage is a deeper data completeness check that runs during processing — errors here appear if a specific data stream required by the assessment method is absent from the extracted variables.
Stage 1 — Structural validation (shown immediately after file selection)
| Error message | Cause | Fix |
|---|---|---|
| File not found. | The file no longer exists at the path that was selected — it may have been moved or deleted. | Browse for the file again from its new location. |
| Please select a valid .mvnx file. | The selected file does not have a .mvnx extension. |
Select the correct .mvnx file exported from MVN Analyze Pro. |
| MVNX file is not valid XML: [detail] | The file is corrupted or was not written completely during export. | Re-export from MVN Analyze Pro. |
| Not a valid MVNX file (missing subject element). | The file does not have standard MVNX structure. May be from an incompatible version or a different Xsens product. | Re-export using MVNX version 4. |
| MVNX file is missing frameRate. | The <subject> element lacks a frameRate attribute. |
Re-export using MVNX version 4 with all data points enabled. |
| MVNX file has no T-pose frame. Please re-export from Xsens MVN Analyze Pro. | The T-pose frame was not found in the file. This typically means the file was exported with a limited data selection or without all data points checked. | Re-export from MVN Analyze Pro with MVNX version 4 and all data points checked. |
| MVNX file contains no motion data frames. | The file has no normal motion frames — it may be a calibration-only file. | Ensure you are exporting the full session, not just the calibration. |
| MVNX frames are missing orientation data. | Orientation data was excluded during export. | Re-export with all data points checked. |
| MVNX frames are missing position data. | Position data was excluded during export. | Re-export with all data points checked. |
Stage 2 — Data completeness validation (shown during processing)
If the structural check passes but a specific data stream required by the assessment method is absent from the extracted variables, an error appears during processing. The message pattern is: "Please export [data name] data in .mvnx." — for example:
- Please export trunk bending angles data in .mvnx.
- Please export left hand positions data in .mvnx.
- Please export right wrist angles data in .mvnx.
The fix for all stage 2 errors is the same: re-export from MVN Analyze Pro with MVNX version 4 and all data points checked. These errors indicate that individual data streams were deselected during the original export.
6. After a Successful File Load
When the file passes validation, the app saves the file path and immediately navigates to the Input Configuration page for your chosen assessment method. From here you can:
- Preview the motion capture data on the playbar and set trim markers to define the active analysis window
- Define one or more lifting tasks — time windows corresponding to individual load-handling cycles
- Enter task parameters and metadata
- Click Process to run the analysis
These steps are covered in full in the Getting Started with Motionprint Ergo guide.