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Extended Tracking Question

Unity Editor
September 16, 2022 - 8:48am #1

Hello, I am new in ar development and doing my capstone project where the user scans a ground plane and spawns an ar object/world. I am currently facing a problem where whenever I face a wall or other similar scenarios, the ar object disappears, I also have already enabled the extended tracking option. Is it possible for Vuforia to keep the ar object in place(the first position it was spawned) and active at all times especially when the camera vision is blocked by real world objects?


Extended Tracking Question

September 16, 2022 - 9:33am #2


The use case you've described, Engine keeping an augmentation in the position that it was placed, is the primary use case for the Ground Plane feature. However, due to our algorithm's implementation and the current state of device technology, there are limitations in the robustness of performance.

The core of the Ground Plane feature is implemented using Device Tracking. As described in the linked article, Device Tracking uses a combination of visual features (from the device's camera sensor) and device orientation (from the device's IMUs). The former is used as part of the plane detection functionality, and the latter is used for robustness of the 6DoF pose returned to the application. Both are equally important to the performance of the feature. This makes it necessary to stage Ground Plane experiences in settings that enable the camera to accurately capture the details of the surroundings. 

Some basic recommendations:

  • Stable lighting conditions
  • Moderate lighting - not too bright or too dark
  • Avoid glare and dark shadows
  • Surface details help to reveal geometry and improve accuracy and performance

Facing a wall or covering the camera denies the algorithm from extracting visual features from the surroundings. This hurts performance and can lead to a loss of tracking (i.e. your augmentation disappears from the anchor point).

Device orientation data (from the IMUs) can help to 'bridge the gap' when visual information is not available, but gyros tend to drift which can lead to augmentations floating for flying away. Thus, they cannot be solely relied upon for accurate poses over extended periods of time.

Here is a detailed article about Best Practices for Continued AR experiences which you may find helpful. It talks about some of the limitations and additional APIs that can be used to help your application provide better Ground Plane experiences.

Thanks for your interest in Vuforia Engine!

Kind regards,

Dave Downing

Vuforia Engine Technical Support

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