To draw a 3D Graph with KAlgebra select the 3D Graph tab and you will see an input field at the bottom where you will type your function. Z cannot be defined yet. For the moment KAlgebra only supports 3D graphs explicitly dependent only on the x and y, such as (x,y)->x*y, where z=x*y.
The view can be zoomed and moved with the mouse. Using the wheel you can zoom in and out. Hold themouse button and move the mouse to rotate the graph.
The left and right arrow keys rotate the graph around the z axis, the up and down arrow keys rotate around the horizontal axis of the view.
In the menu you find these options:
Enable or disable transparency in the 3D graph menu
Save (Ctrl+S) the graph as image file
Reset the view to the original zoom in the 3D graph menu
You can draw the graphs with dots, lines or solid styles in the 3D graph menu
Below is a screenshot of the so-called "sombrero" function. This particular graph is shown using the 3D graph line-style.