Model Targets Supported Objects & CAD Model Best Practices

Objects with colored or patterned surfaces typically work better. Objects in a single uniform color are difficult to track, though they can be reliably detected. Some variation in surface appearance is required to distinguish the object. For this reason, a pure white object on a pure white background or pure black objects on very dark backgrounds may not work well.
Similarly, objects that are mainly black, transparent or highly reflective may also make detection and tracking difficult since they do not provide sufficient surface details.
Sometimes 3D printed objects made from a single-color material may also be difficult to track.

NOTE: The color of the physical model does not necessarily have to exactly follow the color in the CAD model used for target generation. One Model Target database may be used to detect and track color variations of the same product.

Geometric complexity is key to distinguish an object from other shapes in the environment. Simple shapes such as cubes, spheres, or very elongated simple shapes may be easily confused with other objects in the user’s setting.

Try to base your experience on products or objects that have enough sharp edges, dents, bulges, etc.

It is recommended to avoid symmetric objects as the Model Target tracker won’t be able to tell its sides apart. Additionally, repeated parts, such as identical extrusions on a surface, can further cause confusion for detection and tracking.

While the Model Target tracker can tolerate some deviation between physical and digital model, expect that objects that articulate and/or flex may fail to be detected or tracked effectively.
As a best practice, remove parts from the CAD model that are not always present on the physical object (e.g. one variant of a product has some small attachment that is not present in another) or parts that are known to move.
This however only works if most of the object is rigid. Objects that mostly consist of articulated or flexible parts are not supported.

Physical objects should have the exact same shape and size as their 3D CAD model used for target generation. It is important to have a strong overlap for the robustness of the experience.
While wrongly scaled objects might be detected, tracking performance will be sub-par if metric scales don't correspond between the physical and the digital object.
Because of that, make sure that your model target is set to the correct size of the physical object in meters as accurately as possible.

For practical reasons - since sometimes CAD models just don't represent the physical object 1:1 - the Model Target technology can tolerate up to 10% of deviation between the real and virtual object as a compromise. See Best Practices for Scaling Model Targets for more information.

It can be helpful to add textures to your model if these provide visual fidelity and resembles the physical object. The textures can be surface patterns, labels, prints, or flat elements - such as gauge-backplates.

Such details help Vuforia Engine extracting the necessary information from the geometry and improves detection and tracking; though, the final detection and tracking performance depend on many run-time factors such as lighting intensity and color. The Model Target Generator will provide a warning if it detects missing textures on a model.

The currently supported texture formats are JPG, PNG, and PGM in either 32-bit, 24-bit, and 8-bit. Have this in mind when importing models to the MTG, as using other file formats for your CAD-model texture may result in import errors.

Models sometimes tend to have cracks in their polygonal representation. This typically results from wrong tessellation, simplification, or combination mismatches. Try to avoid these as such holes create unnecessary, false details on the object that create computational overhead and potentially lead to false detections. Tip: Modern CAD software packages can verify the models for holes and cracks prior to 3D printing, such a tool can be helpful to verify your model before working with Vuforia.

During the conversion pipeline, some parts of a model might be corrupted, have wrong (transparent) material properties, or simply be missing in an assembly filter. Visually compare the loaded CAD model in the Model Target Generator to contain all your desired parts, visually matching with the physical object to be augmented.

NOTE: As explained above, in case parts are known to be non-rigid (moving) it is recommended to remove them from the model.

Normals facing the wrong direction - away from the physical surface normal - might cause mesh elements not to render leading to various side-effects. Additional edges, visible inside objects of a complex model, screen-door effects on surfaces, etc. can create a wrong visual representation of the CAD model and result in low detection and tracking performance. Incorrect normals can also yield apparently missing parts, see above section. Visually verify the integrity of normal distribution, some packages provide tools to conform normals.