Capture 3D Scene

I’ve used or ofxVectorGraphics to save my openGL screens as PDF files. It worked well while I used two-dimensional drawing stuff. But now I tried to draw some three-dimensional stuff using ofxLine() and set up a camera (ofxCamera). It works well on the screen, but when I try to capture the screen with gl2ps it writes an empty file. What’s wrong?
I guess it’s something with the camera, because if I draw some two-dimensional ofLines too, I can’t see them on the screen (only the 3D ofxLines) but they appear in the captured PDF (only the ofLines).

I did something similar, did you save the screendata before remove the camera.

    // texScreen is ofTextureAdv  
    // be sure save the image befor remove the 3d camera