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I'm trying to create a basic scene an AR.JS with NFT (so it's not just the basic marker-based tracking; it tracks a custom image) using A-frame to place down and position my objects, but I've noticed that e.g.: if I place a 1*1*1 size box in the scene, it will appear at different places on different devices. And also, if I don't scale it up to like 200, it will appear as a very-very tiny box.

E.g.: If I try to view my scene on my phone, the object appears at the exact center of the marker, but if I check it on a different phone, it will appear almost completely outside the marker. Also, if I check it with a webcam, it will appear yet again in a different place, and even in a different size.

I wonder if there is any option to make the marker images bottom left (or any other) corner the 0 0 0 point, so I can position my objects more precisely, and also set the object's width to equal the marker images width, so I don't have to scale up the object like this.

Jonathan Leffler
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Miklós Szabadi
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1 Answers1

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At this moment there is any option to display a model in the center of the NFT marker. This because AR.js depend on jsartoolkit5 and this last has no yet this feature. But if you know the width, height and dpi you can display the object in the center of the maker with this formula (pseudo code):

obj.position.y = (marker.height / marker.dpi * 2.54 * 10)/2.0;
obj.position.x = (marker.width / marker.dpi * 2.54 * 10)/2.0;

You can acquire width, height and dpi while creating your marker or using the dispFeatureSet display app distributed by the Artoolkit5 SDK you can find binaries here https://github.com/artoolkitx/artoolkit5/releases/tag/5.4.0 or from artookitx website https://www.artoolkitx.org/docs/downloads/

kalwalt
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