A Multi Target is a collection of multiple Image Targets combined into a defined geometric arrangement such as boxes. This allows tracking and detection from all sides and can serve numerous use cases in, for example, marketing, packaging, and in instructional contexts. Start by creating your Multi Targets in the Vuforia Target Manager and upload your images fitting the dimensions of your Multi Targets.
Using Multi Targets
Common uses of Multi Targets include recognizing and augmenting printed media and product packaging for marketing campaigns, gaming and visualizing products in the environment where the product was intended to be installed and used.
Multi Targets functions in such a way that all of the faces of a Multi Target can be tracked at the same time because they have a shared pre-defined pose relative to Multi Target’s origin. This enables the entire Multi Target to be tracked when any of its child targets has been detected. In this way, Multi Targets provide a single tracking reference for its child targets.
Check out the Multi Targets Sample within the Vuforia Core Samples and use it as a starting point in your Unity or Native app project.
Multi Targets use JPG or PNG images in RGB or grayscale. The size of the input images must 2.25 MB or less. Features extracted from these images are stored in a device database, which can then be downloaded and packaged together with the application. The database can then be used by Vuforia Engine for run time comparisons.
Multi Targets should ideally be viewed under moderately bright and diffuse lighting. The surfaces of the object should be evenly lit.
Refer to this link to see more information on The Physical Properties of Image-Based Targets.
Creating and Managing Multi Targets
Preparing and Designing Multi Targets
Multi Targets are created in two steps. Firstly, the design and prepare your images for each side of the Multi Target fulfilling both the matching dimensions and the ratings of a good Multi Target. For more information on designing Multi Targets, please refer to Recommendations for Designing Multi Targets. and Best Practices for Designing and Developing Image-Based Targets.
See also the guide Image Targets Optimization Techniques for tips and tricks to improve images for better AR quality experiences.
Creating and Multi Targets
The second step is to create the Multi Target through the Vuforia Target Manager. When a target is added to a database, you can select and create a Cuboid. This is an empty Multi Target which allows you to quickly create a cube or box and define its dimensions, height, width, and length. Specify the dimensions of the Cuboid and database according to your printed physical version and input the dimensions in preferably meters. Once the Cuboid is created, you can select and open it, and upload the images of each of the six sides of the cuboid which also will evaluate the star rating of your images. For a complete guide on creating Multi Targets and device databases, please visit How to Work with Device Databases.
As an alternative, you can define the Cuboid arrangement in the config.xml file of target's dataset or at runtime. See How to Modify a Multi Target Using its Config XML File for more information. Or add the images to your Multi Targets at runtime.
Using Device Tracking with Multi Targets
Device Tracking improves tracking robustness by using features of the environment surrounding the target. It enables you to use larger models and to place them farther away from the target. Benefit from the concept of Extended Tracking that enables tracking of the target even when the Multi Target is no longer in view. Learn more at Device Tracking.
Using Multiple Targets Simultaneously
Vuforia offers simultaneous tracking of targets and target types. Let multiple Multi Targets work together to apply target dependent functions and events or reward collection by displaying unique augmentations when all boxes are in view.
Visit Detect and Track Multiple Targets Simultaneously for more information.
Multi Target API Overview
The Multi Target is tracked by the ObjectTracker as the Multi Target is part of the ObjectTarget trackable. The corresponding TrackableResult (in this case a MultiTargetResult) provides a common pose, as opposed to the individual status and pose information provided for the individual Image Targets.
Refer to the ObjectTracker API Overview for more information.