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Model Recognition and Multiple Model Targets

March 7, 2019 - 10:16am #1

Hello There,

I am trying to build an app for the HoloLens to recognise multiple model targets, one at a time.

I used the "Model Recognition" to load a database with multiple model targets and multiple guide views. I used the option "Instantiate Model Targets" on the Model recognition to create Model targets for the included models in the database.

I was able to see the guide views of the model targets and switch between them when a model in the field of view. However, the detection of the model did not start.

I am just trying to detect model targets and superimpose their 3D models on top of them with an ability to switch between model targets in the same scene.

Any advice?

I am using:

- Unity 2018.3

- Vuforia 8.0



Model Recognition and Multiple Model Targets

August 7, 2019 - 12:56am #4


There are actions you can take to improve the detection of your 3D model when using the Model Targets Feature:

  1. Correct scale of the model is important for detection and tracking. Confirm that the scale of your CAD model is an accurate representation of your physical model. We also recommend using meters as your unit of measurement.
  2. A more detailed model should provide a better tracking experience. While higher poly counts can work, we recommend keeping the count below 100k for best performance.
  3. Which elements to remove from your 3d model may depend upon the experience you're trying to create. For example, if you want to detect a car from an exterior vantage point, then the interior elements are not going to provide benefit to detection and tracking and as such you can consider removing them.
  4. Connected or fused meshes do not necessarily improve performance.
  5. Remove transparent geometry from your CAD data. For example, if you are trying to detect a car, it is recommended that you do not include any of the windows or lights in the CAD model that will be used for the Model Targets dataset.
  6. Include texture differences in your CAD model. Using the car example again, if the car has a decal painted on it or has a segment, such as the hood, that is a different color from the rest of the model, make sure that is included in your CAD model. This difference in texture will be used in the detection of the target, although it is difficult to quantify how much this can improve performance.
    • The current Model Targets is not designed to work with realistic-looking textures with many different colors. They work best with single-colored surfaces that contain logos, etc.
    • There are two ways to add these elements to the 3D model:
      • Map a texture onto the model. The texture image should ideally come directly from your design software and not be from a scan of the object.
      • Use geometry with different colors. Different colors will be considered as different materials. No special material IDs are needed.
        • The “different colors” used *do not* need to match the actual colors that appear on the physical object. The difference in colors will provide the geometry needed by the SDK for detection.
  7. Use different colors on the model when there are different materials or colors on the real object. While Model Targets is designed to detect objects by shape, giving additional information on the materials will often greatly improve detection robustness.
    • There is no need for model colors to match the colors of the real object - the specific color is not relevant, just the differences in colors.
    • Colors can be used to indicate different parts with small gaps in-between that are strongly visible but are difficult to extract from a rendered view. One example is the area between the body and the door of a car.
    • If possible, avoid single-color models and file formats that can’t transport color information such as STL.
  8. Simplification tools, such as Simplygon, are able to process logos and transform them into geometry (edges). However, if you used Blender for simplification, it may destroy this info.
  9. Model Targets is designed to be used with CAD-like models that use only a few colors to indicate different materials. Please avoid photorealistic textures from game-like models, or photogrammetry scans. If you need to use photogrammetry scans, please remove the texture before importing into the MTG.
  10. Try a different guide view for your target. If the guide view you are using doesn't contain enough of the geometry of your target, you may encounter issues detecting it. Often times a slightly angled view of the target will provide better results than a direct front view of the target.
    • Recommended to avoid front-parallel viewpoints and choose diagonal views for detection, where possible.
  11. There are a few of different approaches to a different guide view you could try that may result in better performance:
    • Try zooming in on the section of the object with the most geometry for your guide view, while keeping the rest of the model out of the view of the guide view. This will allow detection to be based off a smaller portion of the Model Target that is rich in geometry, but also will keep the rest of the model present. While moving back to see the rest of the model you will begin mapping the surroundings and likely end up with a better tracking experience.
    • Another potential guide view would be closer, but at an angle from the front-left or front-right of the object. This will allow you to get the full object in view, but also start closer and allow more tracker mapping as you move around the object.
    • Avoid highly cluttered areas on your object as detection views, such as areas with heavy wiring or highly repeated structures. Choose a view that has sufficient distinctive geometry without too many small details. It is not necessary to see the whole object for detection, but you can zoom in onto a suitable area if that is feasible for your application.

Note: Material differences are used for Model Target detection, but they do not appear in the guide view. Thus, the guide view is not the final indicator for object geometry

Thank you.

Vuforia Engine Support

Model Recognition and Multiple Model Targets

August 6, 2019 - 2:12am #3


         My target recognition of model target is not working effectively. I runned apk in one plus 6 mobile did I want to add any script or update project setting in unity.

        I am using trail version of unity-2018.3.14f1

       vuforia-8.1.7, MTG-8.1.8.


Model Recognition and Multiple Model Targets

March 13, 2019 - 2:01pm #2


I was just doing some evaluation of trained Model Targets on HoloLens and things worked well.

Does the guide view disappear when the target enters the HL's field of view? Or is it always visible?


Vuforia Engine Support

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