Hpl Model Editor.. How?

[Mudbill]

You don't need to see the whole map at once to be able to make a big map. Yes, there is a limit to how far out you can zoom, but you can still move everywhere around the level. Hold the alt key down, then use M1 (left mouse button) to rotate, M2 (right mouse) or scroll wheel up and down to zoom and M3 (middle mouse (press mouse wheel down)) to pan the camera (as in move it around the level).

If you need to move up, use the grid option. You can use the LT button to lock the pivot point of the camera to the grid or not.

Lastly, there's the F key. If you select something, you can press F to make the camera focus on that object by placing the grid on the object's level and zooming in. You can also use ctrl+F to find a certain object and focus it.

Other than that, I don't think there are other ways you can navigate, but why would you need anything else? You don't seem to be able to explain your problem well enough for us to give you a solution.