Let's suppose that I put some 3d model in the view and I wanna play a video (maybe with some trasparencies) when the user come close to the model.
Is there any way to achieve this?
almost 10 years ago
Yes this is possible:
If you're using a GeoLocation for placing your 3d Model you can implement the onEnter and the onExit functions of the ActionRange
For 3d Models on an image recognition target there is no such functionality. But you can reach this by creating two targets (Tracker). Create a first tracker with the image you want to use for displaying the 3d model, and use the same image but a magnified cropped version for a second tracker. When you move your device closer to the target the second tracker will be recognized. You can react on it by implementing the onEnterFieldOfVision/onExitFieldOfVision functions of your tracker's Trackable2DObjects.
One more thing: 3d Models are rendered on top. So a VideoDrawable will always be rendered behind the 3d Model.