I have an orthogrphical view. When I draw transparent objects, the last drawn one is in front of all other object. How can I get a later drawn (or last drawn) object behind all other objeczs?

Thanks for helping,
Volker Mische

Either sort them for depth using quicksort (or other sorting algorithm), or use BSP trees to sort the polygons

How can i change the order of the objects?
Can i edit the depth buffer?

You can change the order of the objects using some kind of sorting algorithm. As Rob has said, for example, the Quick Sort.

There are only two options:
a) Enable Z-buffering with glEnable(GL_DEPTH_TEST); Be sure the objects Z coords are correct.
b) Sort your objects to render them in the order you want. Disable Z-buffering.