Best Practices for Preparing and Scanning an Environment

Area Targets are a type of target that can be used to track parts of your surroundings. It offers unique opportunities for augmenting any part of the environment that was present during scanning. In order to use Area Targets, special hardware is required for scanning the chosen environment and each scanning device has its own guidelines. 

This article explains of the practices for choosing, preparing, and capturing an environment. The article is divided into sections that describe practices for supported scanning equipment such as professional 3D scanners or handheld scanning devices using LiDAR. For a list of devices capable of creating scans suitable for Area Targets, please see the Area Targets Overview page.

Scanning equipment can be grouped into professional and handheld scanners.

  • Professional scanners are high-performance devices capable of covering large areas, returning highly accurate 3D models as colored point clouds and high-quality HDR panoramic images. See our Leica and NavVis documentation for more information.
    A special class of these scanners is best suited for scanning medium-sized spaces with good accuracy and panorama images, such as the Matterport™ cameras. See our Matterport™ documentation for more information.
  • Handheld scanners can capture room-sized spaces, producing a 3D model well-suited for tracking and authoring. The scan quality is fair but less accurate, and the scans have fewer details compared to professional scanners. In addition, the scanning duration is limited to short capture periods, constraining the size of the space you can capture. The Vuforia Creator App is an integrated solution to provide direct, on-device Area Target generation.

Please follow the corresponding section of this page on best practices based on your scanner or scanning solution.

Choosing Environments

The space should be static; objects included in the scan should be fixed and unlikely to be moved. In environments such as exhibition booths or office spaces with many movable elements or persons, verify that enough portions of the surroundings—such as wall decorations, ceiling-based installations, floor coverings, stable furniture, or similar—are always visible during the intended augmentation scenarios.

Scanner Selection Guidelines

Exhibition booths, small cafés, apartments, production lines, factory floors, shops, museums, and even airports are all suitable candidates to scan and track as an Area Target. As diverse as these environments are, as different are the solutions and equipment that exist to scan them in 3D. Due to differences in the layout and complexity of the spaces and their visual appearance (cluttered vs. empty; sunlit vs. windowless, etc.), choosing an appropriate scanning method can be difficult. To select the most suitable scanning device, follow our recommendations based on the size of the space to be covered:

  • 10 m2 up to 50 m2 or 500 sq ft are best captured with the Vuforia Creator App or Vuforia Area Target Capture API.
  • 100 m2 up to 1000 m2 or 10,000 sq ft and medium spaces are best captured with the Matterport Pro2 & Pro3 and Leica scanners.
  • Spaces up to and beyond 30.000 m² or roughly 300,000 sq ft are of considerable size and best captured with NavVis scanners and the Leica RTC360. Such large spaces are, in practice, sliced into separate scans and processed individually for convenient authoring and better performance.

NOTE: Large Area Targets are represented by larger datasets which require the use of the setExternalPosition() API to help localize the user in the vast area. See Area Targets API Overview for more information.

Preparing the space

  • Inspect the space, tidy up the environment, and remove items you do not wish to include in the scan.
  • In indoor spaces, minimize incoming sunlight from windows. Scans on overcast days will not create hard shadows and provide average lighting: not too dark or bright. At the same time, ensure the space provides enough consistent artificial lighting, e.g., switching lamps and lights, providing a typical lighting scenario.
  • Open doors within your space to allow for good registration between scan locations.
  • Close the doors to rooms and spaces that are not to be included.

Outdoor spaces

Outdoor scans are a particular circumstance that not all depth scanners support. An outdoor environment is further influenced by changing daylight, seasons, shadows, and growing vegetation, which makes it challenging to construct a reliable Area Target that tracks well. However, we have seen customers succeed with creating augmented outdoor experiences.

  • If scanning an outdoor environment, scanning on overcast (cloudy) days will produce the best scan as it minimizes variations due to harsh shadows from the sun.

Scanning Practices for Professional Scanners

Planning your path and scan positions

Before scanning, you should follow a normal walking path through the space. Mark the scanning positions with tape in a grid-like pattern with an average of (6.5ft) apart and 0.6m (2ft) from walls, doors, and objects. Remember to ensure a clean line of sight between each scan position and to capture the entire space without distortions, slices, or warps.

  • The greater the complexity of the environment's geometry, the closer your scan positions should be to one another. Ensure that natural points of interest (e.g., at a workstation, desk, or machinery) receive additional scans closer together with a distance of 1m (3ft) apart.
    • This practice aids Vuforia Engine’s relocalization capabilities and accuracy as one moves through a space with complex geometry, which consequently has more visual changes and parallax effects.
    • However, an increased scanning density may result in a larger target DAT size and a greater CPU/memory usage when the Engine is running the Area Target on your device. As a result, we don’t recommend scan positions less than 1 meter apart.
  • For large open spaces with less geometric complexity, scan positions can be further apart with a scanning distance of up to 3m (10ft). Scanning distances can be even further apart if the space is an open area without nearby geometry, and the tracking accuracy is not critical.
  • Avoid marking scanning positions in corners or too close to walls.
    • In cases where you move around a corner, also mark down a scan position at the corner’s edge.
    • For doors, there are different guidelines depending on the scanning device:
      • Matterport™ scanner should scan before and after entering a new room while maintaining the distance mentioned above.
      • Leica scanner should scan in doorways to link to the previous scan position.

In both cases, it is recommended that doors within the space be kept open, while doors to spaces that are not to be included in the scan are shut.

The above illustration shows an example of the scanning path for the Matterport™ Pro2 or Pro3 camera.

During scanning

Avoid scanning while there is activity in the space. Similarly, you should also stay clear of being present in the scans.

If possible, monitor the scanning progress via a provided application on a tablet to ensure the new parts are aligned correctly between scans. Correct failed scans by re-scanning the position or moving closer to the prior scan to achieve a better result that is compatible with your model.
Each professional scanner has its particular scanning practices, which we encourage you to study beforehand. For each brand, we have summarized a few in their detailed guides:

Completing the scan

Completing the scan depends on the scanning device and the associated post-processing software. The raw scan data is likely transferred from the device to a processing software where the scanned data are registered together into a consistent 3D model of the environment. 

Review the new digital model for missing parts or inconsistencies, such as misalignments and broken links. Cleaning and trimming the scan may also be increasingly challenging if the scan was captured outside where distant objects, e.g., a long street, are included.

Scanning Practices for Handheld Scanners

Planning your path and scanning motion

With smaller spaces, it is also advisable to plan a path. The distance to surfaces and objects should be scanned between 0.5 m (2 ft) and 2 m (6.5 ft). Scan the area fronto-parallel, which means only scanning surfaces and objects directly in front of you.

  • Prepare a path along the walls or boundaries that will allow you to scan all the major features in the room. Scanning the same area multiple times may introduce surface duplication in the reconstruction. Therefore, choose a start and end position near each other, preventing you from rescanning your start position.
    • The path should be laid out so, if possible, you only scan an area once.
  • Tables and flat structures such as screens do not require to be scanned from both sides.
    • Similarly, scanning beneath, behind, or around objects considered inaccessible and unlikely for users to approach is better to exclude than include.
  • Complex objects such as vegetation are difficult to capture in detail.
  • Transparent or reflective surfaces are captured poorly by handheld scanners, and it is recommended to avoid scanning them or covering them up.

NOTE: Scanning empty rooms provides insufficient features for Vuforia to track.

If you are scanning multiple spaces with the Area Target Capture API and plan to align them to a common origin, you should adjust your scanning path to overlap slightly between the scans, as this helps compute the alignment between two targets. However, you should still make sure that your scanned space is visually different from the area that you align with. See information about aligning Area Targets in the Area Target Capture API for Unity and for Native.

an illustration of a scanning path without loop closure.

During Scanning

Depending on the device, there may be varying directions for achieving a successful scan. We have found that moving at a steady speed and scanning in an up-and-downwards continual motion provides good results. The Vuforia Creator app overlays a live mesh that offers a helpful indication of the captured parts of the environment. 

  • Scan aligned (fronto-parallel) to your room's surfaces (walls and other facades) and scan an area only once.
  • Scan in vertical motions (up and down).

an illustration of a fronto-parallel and continuous scanning motion in front of a wall.

  • Avoid too-fast motions and rotations; they are likely to break the scanning process or result in a warped reconstruction.
  • Maintain a scanning distance of 0.5 - 2 m (1.5 – 6.5 ft).
    • Avoid scanning an area you are approaching from afar (more than 2 meters), and instead, enter that area within the recommended distance range.

 

Completing the scan

The Vuforia Creator App has a time limit and will automatically conclude the scan if that time is reached. Furthermore, the app can generate an Area Target directly from the scan and let you test it right after. You can then investigate if the scanned space is tracking well within one session. See the Vuforia Creator App for a complete guide

Assisting Area Target Tracking

Rooms and environments with more unique features and objects tend to do better in tracking and re-localization. In environments containing repeated structures and/or multiple instances of the same objects, tracking locations may be mistaken for one another or not be recognized. To accommodate spaces with fewer features or repetitions, we recommend adding extra features such as prominent objects or markers that can aid the tracking, or you may use the location prior for (first-time) localization. See the Area Target API Overview for more information.

Reflective and transparent surfaces are commonly challenging to capture. If the environment possesses glass walls, glass tables, or a large surface with a glossy metal with reflections, consider covering such surfaces or just not scanning them

Learn More

Creating Area Targets

Vuforia Creator App

Area Target Generator

Testing Area Targets

Area Target Test App User Guide

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