As written in the Vuforia SDK forum by the admin:

Creating a trackable:
First, you will need a 2D image that meets certain guidelines (see the developer guide for more details). This can be a photograph or hand-drawn image with sufficient detail. Go to My Trackables to upload your image. The online tool will process the image and create the data files required by the SDK to recognize the trackable object.

Where do I put the trackable files?
These should be placed in the assets folder of the Android project.

Building your project:
There are two steps to building. First, you must build your native code into a shared library, to be loaded by Java. This is done from the command line, by running “ndk-build” from the project’s root directory. The Android NDK has its own build system and make file format ( Then, you can build the application binary (apk file) from Eclipse. Note: you may need to refresh the project (F5) after rebuilding the native shared library for it to be bundled correctly.

Adding native code files to your build:
Open the main file with a text editor (located at <project root>/jni/ Here, you can add source files to the LOCAL_SRC_FILES variable.

Debugging your native code:
The debugger built into Eclipse only works with the Java code in your project. For the native code, you can use the ndk-gdb command from the command line (available with NDK r4 and later). You can also add logging, but note that printf output is not available, only logging using NDK-supported functions or the LOG wrapper provided by the QCAR SDK.

Checking your log output:
In Eclipse, go to Window > Show View > Other > Android > LogCat to pull up a running view of the log. Note: sometimes the log begins clearing itself every line, making it impossible to follow – if this happens manually clear the log with the button in the upper-right corner of the pane to reset it. You can also view the log from the command line, by running “adb logcat.”