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I want to develop an augmented reality application for android that is capable of using markers to generate 3D objects and these 3D objects are interactive upon touch using the mobile's touch input.

I have browsed through the available SDKs like Vuforia , Junaio or Layar Player and found that they all support:

  • Marker detection with 3D virtual image overlay
  • Virtual buttons that get active when you make them invisible. (Vuforia)
  • Interactive video playback.

However, what I am looking for is:

  • Virtual object in AR that can be made interactive using mobile's touch.

I am pretty sure it is possible, as there are virtual video overlays that upon clicking/tap would start a video (similar to an interactive virtual element).

Q. Could someone suggest a library/toolkit best suited for this functionality that I'm looking for?

or

Q. Is there something that I apparently missed during my search with the aforementioned toolkits that already support the functionality I want?

HawkPriest
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  • Hi HawkPriest, Basically, a virtual object is something that you draw, thus you can manage it's interactivity with the mobile's touch. Using any of the AR libraries you've mentioned you can make sure this object will appear when the proper target in the reality is detected. So it is not very clear what it is you are missing - please try to explain what it is exactly that you need. – yakobom Oct 07 '15 at 04:23
  • Hi yakobom, the above mentioned libraries enable marker detection and and virtual image overlay interaction, by that I mean the camera that is responsible for detecting the marker also detects that some part of the image is being occluded and thus enables interaction with the virtual object opposed to using the inbuilt touch of the phone to interact with the "overlay-ed" virtual object. I recently read somewhere a viable technique would be to use ray casting to translate position of touch on screen to camera coordinates and check if it intersects the virtual object. Thanks for the reply!. – HawkPriest Oct 08 '15 at 07:15
  • Hi again. What you say is crrect but these are two different things. Image being occluded, like in Vuforia's 'Virtual Buttons', refer to 'natural interface' - you touch the air in fron of the camera. Thouching the screen on a specific virtual object is something completely different... And yes, this can be done using ray casting (or other methods). In Vuforia's forum they have such example, I believe - but first tell me if this is indeed what you need. – yakobom Oct 08 '15 at 09:00
  • Hi, yes that is what I am looking for. I read those discussions online on the Vuforia developer community forum that you mentioned, however they seem to be addressing Unity and not direct android. Even though if I could export a Unity project to an android project I will have deal with Unity player and I found that the code is not straight forward to manipulate the virtual objects. So I am searching for a simple straight forward solution that addresses directly the touch based interaction on android (maybe via 3rd party libraries). Thanks for the reply again!. – HawkPriest Oct 09 '15 at 16:28

2 Answers2

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According to your last description, what you need is supported by Vuforia, and there is a sample for pure Android (no Unity) as well.

You need to look at the Dominos sample, where they show how to drag an OpenGL domino object on the screen. Look here for a quick description: https://developer.vuforia.com/forum/faq/android-how-do-i-project-screen-touch-target

In case you run into some problems while trying to implement it yourself, you can search at the Vuforia forums for some answers to common problems others have faced with this. But basically, it works well in their sample.

yakobom
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Well, this is for Unity 5.x

First, go through Vuforia's Documentation to know more about Image Targets and AR Camera.

Import your 3D models to the scene so that all interactive objects are a child of the image target.

Read touch on mobile phone (I used android for my project)

if(Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Began)

Convert touch point into a ray from the screen into the 3D world

Ray ray = Camera.main.ScreenPointToRay(Input.GetTouch(0).position);

Create a plane in the scene (for the ray to hit)

Plane plane = new Plane(Vector3.up, Vector3.zero);

If, the ray hits the plane, get the x,y,z position. Value of pos will have the world position

if (plane.Raycast(ray, out distance)){
    Vector3 pos = ray.GetPoint(distance); 
}

Please modify the code according to your need. This is a very basic example.

Saurav Bajracharya
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