still doing something wrong.

Is it correct that the plane normal is (0,0,1) for intersecting with a xy plane?
How do i correctly send the line from the mouse straight into the 3dspace. Have problems with mouse_dir3d etc (yes setting mousepos to mouse_cursor)

and is the origina of the plane correct if (0,0,0) ?

Maybe someone can help me a bit. My brain is cooking here at 30 dgree celcius >.<