Structure Sensor 3 - Known Issues Tracker (Bugs, Stability, Crashes)

Structure team members are frequently monitoring the forums, and developer emails for trending issues facing a variety of individuals. We would like to assure members of the community that we are working to resolve the concerns below, part of which is communicating these issues once we know about them.


If you do not see a bug report that you are experiencing, please follow this form to file a bug report.

Reports are investigated typically within 24-72 business hours, and may require further conversation with the reporting individual. While Structure team members are reviewing your bug report we are looking at:

  • Is this a known bug
  • When was the bug introduced
  • Is this bug reproducible
  • How does this bug impact the community


ST-1532: Opening/Closing Scanning Views Leads To Crash

Bug Name: Opening/Closing Scanning Views Leads To Crash

Status: Open

Description: Opening and Dismissing Scanning views can lead to App Crashes

Impacted Hardware/Software: SDK 3.1 Structure Sensor 3. 

Cause: Initializing or stopping the Structure Sensor 3 is an intensive operation. Both actions call sequences of tasks that have to be executed in the correct order. Attempting to launch a scanning session before the last one is completely closed can force the app to crash.

Solution: A series of updates are planned to both the SDK and the Structure Sensor 3's firmware to improve stability and efficiency. In the meantime, we recommend plugging the Sensor only when prompted to do so by the scanning screen's 'Please Connect the Structure Sensor' message. This will ensure that the App cannot start a new scanning session before the previous one has closed. You can also add a delay to your app's close event handler of 5 seconds, which will make sure that the scanning session has closed before a new one has begun.


ST-1549: Long Initialization/Shutdown Times

Bug Name: Long Initialization Times.

Status: Open

Description: Connecting a Structure Sensor 3 to an app using the Structure SDK 3.1 or later takes an inordinate amount of time - upwards of 10 seconds. Sometimes a black screen is displayed.

Impacted Hardware/Software: SDK 3.1 Structure Sensor 3. 

Cause: Initializing or stopping the Structure Sensor 3 is an intensive operation, and involves loading a large amount of data to the sensor. This process is being optimized, at the moment can take several seconds to fully process.

Solution: A series of updates are planned to both the SDK and the Structure Sensor 3's firmware to improve stability and efficiency. In the meantime, we recommend plugging the Sensor only when prompted to do so by the scanning screen's 'Please Connect the Structure Sensor' message. This will keep boot times to 3-5 seconds, and also increase stability overall.


ST-1319: Structure Sensor 3 Unrecognized by Structure App

Bug Name: Structure Sensor 3 unrecognized by Structure App.

Status: Resolved

Description: Connecting the Structure Sensor 3 to an iPad and running the Structure app will lead to a blank screen, or a message asking to 'Please Connect the Structure Sensor'

Impacted Hardware/Software: Structure App, v2.1.5, Structure Sensor 3. 

Cause: The Structure app requires an update before it can connect to Structure Sensor 3.

Solution: v2.1.7 was released on November 7, 2024, which addressed the connection issue. Note: The Sensor 3 will require that the IR projector be turned on in order to scan in IR mode. (This is controlled by the light bulb icon on the left hand side of the screen).


ST-1297: Structure Sensor 3 will not connect

Bug Name: Structure Sensor 3 will not connect

Status: Open

Description: Despite Structure Sensor 3 Connecting to the iPad, and displaying a blue light (showing a connection), Sensor will not connect to the app.

Impacted Hardware/Software: SDK 3.1, Structure Sensor 3. 

Cause: Structure Sensor 3 features a new chipset, and in some circumstances the connection protocol to that chipset is disrupted. 

Solution: A full fix is being worked on. In the short term, unplugging Structure Sensor 3, closing all apps, restarting the app, then plugging the sensor back in, will clear the issue. 


ST-1208: Auto Exposure Not Supported

Bug Name: Auto Exposure Not Supported

Status: Resolved

Description: IR Cameras can sometimes produce bright or washed scenes

Impacted Hardware/Software: SDK 3.1, Structure Sensor 3, Calibrator 4.5.0

Cause: Auto Exposure, a critical feature for reducing light noise and Sensor Calibration, was not available at launch.

Solution: Sensor 3 FW 1.1 adds auto exposure. To take advantage of this update:

  1. Download the latest version of the Structure App.
  2. Start the app and connect your Sensor 3.
  3. Click the i button in the top right hand corner
  4. Click the update FW button at the bottom of the pane.


ST-1285: Confidence Threshold leads to tracking loss

Bug Name: Confidence Threshold leads to tracking loss

Status: Resolved

Description: When setting confidence threshold above 7, tracking losses are common and the mesh produced has holes

Impacted Hardware/Software: SDK 3.1, Structure Sensor 3. 

Cause: Confidence Threshold is a setting that rejects low quality data. If set to strict (above 7), essential data can also be rejected. This includes data used for tracking.

Solution: Simply set Confidence Threshold to 7 or less. 


ST-1403: Structure Sensor 3 Connects but Original Structure Sensor does not

Bug Name: Structure Sensor 3 Connects but Original Structure Sensor does not

Status: Resolved

Description: An app would work with Structure Sensor Pro/Mark II or Structure Sensor 3, but not Original Structure Sensor

Impacted Hardware/Software: SDK 3.1, Structure Sensor 3. 

Cause: Original Structure Sensor had a different communication protocol than either the Structure Sensor Pro/Mark II or Structure Sensor 3. 

Solution: A workflow was implemented for the user to select their sensor and, depending on selection, turns on support for Structure Sensor Pro/Mark II or Structure Sensor 3, or turns on support for Original Structure Sensor. This can be done with SDK 3.1. Contact developers@structure.io for more information.


ST-1093: Excessive Noise

Bug Name: Excessive Noise

Status: Resolved

Description: Feedback may include excessive noise.

Impacted Hardware/Software: SDK 3.1, Structure Sensor 3. 

Solution: Structure SDK 3.1 included new filtering to fix these issues. Additionally, Sensor 3 FW update 1.1 includes auto exposure, a utility to cut light noise


FW-23: Structure Sensor 3 LED Issues

Status: Resolved

Description: LED Diagnostic lights are not displaying in the correct pattern

Impacted Hardware/Software: Structure Sensor 3.

Solution:  FW 1.1 includes the new light status codes. To get the new codes, simply update to the latest firmware.


Here is a breakdown of the 1.0 LED patterns. Go here to see the new codes.


State Color Pattern
Connected to iOS Device Blue Solid
Connected to PC Green Solid
Battery Charge Only Blue/Green Blink Fast


ST-1371: While calibrating Structure Sensor 3 the ‘WVL’ detection pane refuses to dismiss


Status: Ongoing

Description: When calibrating Structure Sensor 3, the WVL (Wide View Lens) detection popup launches but will not go away/freezes. 

Impacted Hardware/Software: Structure Sensor 3, Structure Sensor Calibrator v 4.5.0

Solution: In the future, Calibrator will be updated to remove the WVL workflow, which will remove the event that triggers the freeze. 

For now, in order to clear the freeze, the app and sensor need to be restarted. Here is how to do that: 

  1. Close the app completely (do not simply background it)
  2. Disconnect the sensor
  3. Restart the app
  4. Reconnect the sensor

This should restart video streaming and allow the pane to dismiss normally.


ST-1375: Calibrator app says ‘Insufficient Sunlight’ but the room is already well lit

Status: Resolved.

Description: When calibrating Structure Sensor 3, the brightness warning will not dismiss, despite being in a well lit room and/or enabling ‘Indoor Mode’

Impacted Hardware/Software: Structure Sensor 3, Structure Calibrator v 4.5.0

Solution: Structure Sensor 3 works using infrared (IR) light. This means that it needs a good source of IR light when calibrating. But this can present a challenge - modern homes or offices are lit by LED lights, which do not generate enough IR light to calibrate the sensor. 


To address this, Structure has released new FW Updates and Updates to the Calibrator App. The two updates work together.

  1. The firmware update updates the software on your Sensor 3, enabling auto-exposure, a crucial technolgy for more efficiently using light when calibrating.
  2. The Calibrator update uses Auto Exposure to allow you to calibrate the Sensor 3 indoors.

A few notes:


  1. Your sensor still calibrates best with sources

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