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3.3 ARTag Tracking not finding anything

Oct 18, 2009 at 3:23 PM

Anyone else having this issue?

I cant even get it to work on tutorial 8?

Everything was working just fine before upgrading to 3.3. 

In tutorial 8 I set markerLibrary = MarkerLibrary.ARTag; is there anything else that needs to be changed? Loads just fine, no errors, I see the cam video just cant detect any markers.

Oct 19, 2009 at 6:01 AM

Probably you're using the old ground board? Please see if the marker board you're using is the same as the current marker board used for Tutorial 8 with ARTag. It's called ground.pdf.

Oct 21, 2009 at 9:11 PM
Edited Oct 21, 2009 at 9:18 PM

Ohan, I am having the same problem with ARTag in the new version and also with ALVAR. The program builds and runs fine, and I am using the corresponding markers for ARTag and ALVAR, but when I point the camera to the marker, nothing appears in the screen. Any idea what could be the problem? 


Oct 23, 2009 at 11:56 AM

I'm using ALMAR and I'm having the same problem in tutorial 8, the markers are not recognised.

Oct 25, 2009 at 7:15 AM

Hi all,

Sorry for late reply. Just got back from ISMAR conference.

I just looked into the problem, and it seems like there was a little problem when I did copy & paste from our internal Goblin code to the distribution code for Scene.cs file. There is no problem in the tutorial 8 code.

I will fix this problem as soon as possible.


Oct 25, 2009 at 10:14 PM

Hi all,

I just uploaded a new file that includes the fix in the Scene.cs code. I forgot to copy two lines of codes. You can either re-download this zip file, or get the updated Scene.cs from the SVN repository accessible under "Source Code".

Also, please note that if you're using ARTag, due to a memory conflict for accessing the openGL matrix using ARTag's code with my multi-threaded code, you will need to set State.IsMultiCore to false in order to see the objects overlaid on the ground marker. This used not to be the case since I was updating the marker transformation in the main-loop instead of multi-threaded code, but now I moved the marker update codes to multi-threaded code so that I can eliminate the delay between the marker update and video image update.

As you will notice, without the multi-threading, it runs much slower, so we strongly recommend to switch to ALVAR from ARTag as it is being actively developed and there is a commercial license for ALVAR. If you insist on using ARTag, and would like to have it run faster with multi-threading, then you should comment out lines 1805~1815 and add replace lines 1171~1172 to markerNode.Update(0) in Scene.cs. However, you will see some delays between the marker position and the video image.