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Extended Tracking

February 21, 2014 - 7:46am #1


I am not an expert in programming and I have a problem. I installed Vuforia SDK Android 2.8.7. Everything on Eclipse works good and I can create an App for Android using the Vuforia Samples 2.8.8. Now I'd like to replace the model "Buildings" with a customized model, in order to see a different 3d model with the "Extended Tracking" feature.

I am not good in programming, so I tried to look for all files named "Buildings" in the Vuforia folder, in order to overwrite them. I found these files:




I have created an *.h file using Perl with Obj2OpenGL, so I overwrote Buildings.h and its texture Buildings.jpeg. The problem is:


1) What is Buildings.txt? What kind of information are written there?

2) When I tested my App, even if Buildings.h was overwritten, it was shown the old 3d model and not the new one I created. Why?

3) Is there another easy way to reach the same result?


Thanks a lot in advance!



Extended Tracking

February 24, 2014 - 4:50am #6

The Image Target sample in the "Vuforia Samples" already show how to enable Extended Tracking, please have a look there.

Also, the developer guide contains the relevant information (you don't need to search for this on the Forums):


Extended Tracking

February 24, 2014 - 3:53am #5

Unfortunally I do not have particular familiarity with 3d parsing.

But in the end, my target is to use the Extended Tracking function with a customized 3d model. So, what is the easiest way to do it? What do I have to set in order to use the  Extended Tracking function with (for instance) the "Teapot"?

Thanks again for your help.

Extended Tracking

February 24, 2014 - 2:44am #4

To do this, you will need to implement an OBJ parser and extract the vertex arrays out of it, then save them to the txt file; however, writing an OBJ parser may be not so trivial to do, unless you have some familiarity with 3D formats and format parsing.

Or you may serach the internet for some tools or libraries that can do that (but I am not aware of specific ones).


Extended Tracking

February 24, 2014 - 2:33am #3

Thanks a lot for your kind reply.

I have a complex 3d model as a *.obj, how can I automatically produce this txt file? Is there a software useful to write such a list of vertex and texture coordinates? 


Extended Tracking

February 21, 2014 - 8:26am #2

Buildings.txt is a simple text file which contains a list of vertex and texture coordinates; it does not correspond to any specific 3D format (such as OBJ or other well-known formats), but is is simply a plain list of coordinates.

The sample code to read such list is in the Java file (see the loadModel() method).

The Buildings.txt is basically "derived" from the Buildings.h file, but if you want to see any effect in your Java-based sample, you need to modify the  Buildings.txt file.

Technically, you can create such a file by yourself, as you need to specify the following information in such file:

first line: an integer that specifies the number of vertices

then, a list of coordinates (every 3-coordinates you have a 3D point) corresponding to the vertex array of your geometry,

followed by a list of texture coordinates (every coordinate-pair makes a (U,V) texture coordinate)


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