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3D Assets

It's an augmented reality app, so it's not fun without some 3D assets!

Adding assets​

The first thing we need to do is to add some assets to the scene. In AFRAME, we do this by a-assets. Add this block of code inside the <a-scene/> element


<a-assets>
  <img id="card" src="https://cdn.jsdelivr.net/gh/hiukim/mind-ar-js@1.1.4/examples/image-tracking/assets/card-example/card.png" />
  <a-asset-item id="avatarModel" src="https://cdn.jsdelivr.net/gh/hiukim/mind-ar-js@1.1.4/examples/image-tracking/assets/card-example/softmind/scene.gltf"></a-asset-item>
</a-assets>

The first one is actually our target image. The second one is a 3D model in gltf format. AFRAME basically supports all the standard 3D format, so you can probably replace it with the models of your choices later.

Construct the scene​

Now we can replace the dull rectangular plane in the earlier example with an image asset.

<a-plane src="#card" position="0 0 0" height="0.552" width="1" rotation="0 0 0"></a-plane>

Also, we will add an animated 3D model on top of the image.

<a-gltf-model rotation="0 0 0 " position="0 0 0.1" scale="0.005 0.005 0.005" src="#avatarModel" animation="property: position; to: 0 0.1 0.1; dur: 1000; easing: easeInOutQuad; loop: true; dir: alternate">

The scale of the 3D model we use here was normalized to -1 to 1, therefore we set an appropriate scale 0.005. We also have an animation to make the model oscillate between 0 to 0.1 in z-axis. We will not go into the details of the animation, but they are just standard AFRAME stuff.

Finally, we have also modify some rendering properties inside <a-scene> (Optional)

color-space="sRGB" renderer="colorManagement: true, physicallyCorrectLights"

Sorry, I'm not entirely sure what that does, but it seems like the rendering is prettier. You can skip this and still see the effect, not a big deal.

Putting it together​

Putting it together, your html page is something like below.


<html>
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <script src="https://cdn.jsdelivr.net/gh/hiukim/mind-ar-js@1.1.4/dist/mindar-image.prod.js"></script>
    <script src="https://aframe.io/releases/1.2.0/aframe.min.js"></script>
    <script src="https://cdn.jsdelivr.net/gh/hiukim/mind-ar-js@1.1.4/dist/mindar-image-aframe.prod.js"></script>
  </head>
  <body>
    <a-scene mindar-image="imageTargetSrc: ./targets.mind; showStats: true;" color-space="sRGB" renderer="colorManagement: true, physicallyCorrectLights" vr-mode-ui="enabled: false" device-orientation-permission-ui="enabled: false">
      <a-assets>
        <img id="card" src="https://cdn.jsdelivr.net/gh/hiukim/mind-ar-js@1.1.4/examples/image-tracking/assets/card-example/card.png" />
        <a-asset-item id="avatarModel" src="https://cdn.jsdelivr.net/gh/hiukim/mind-ar-js@1.1.4/examples/image-tracking/assets/card-example/softmind/scene.gltf"></a-asset-item>
      </a-assets>


      <a-camera position="0 0 0" look-controls="enabled: false"></a-camera>


      <a-entity mindar-image-target="targetIndex: 0">
        <a-plane src="#card" position="0 0 0" height="0.552" width="1" rotation="0 0 0"></a-plane>
        <a-gltf-model rotation="0 0 0 " position="0 0 0.1" scale="0.005 0.005 0.005" src="#avatarModel" animation="property: position; to: 0 0.1 0.1; dur: 1000; easing: easeInOutQuad; loop: true; dir: alternate">
      </a-entity>
    </a-scene>
  </body>
</html>

The effect is what we saw in the Overview. Easy, right?

img