I have an ortho camera that has it’s center focussed on say (-1000, 500, -1000), where my up vector is ‘z’. Now i want this camera centered on this vertex( top view) This all works so far. But i have problems with clipping everything above the z value of the vertex, right now my walls, roofs etc. etc. are also drawn. So How do i set the correct near value;
You need to figure this out from your application. I didn’t fully understand your explanation. If you use glOrtho as opposed to gluOrtho2D, then the near_val should be the distance from the eye point to the near clipping plane (i.e., probably just a little before the first geometry you don’t want clipped).