Short answer: route norm/cell into [swiz z].
Longer answer: The cell and norm operators will have as many dimensions as there are dims in the matrix/texture coming to the jit.gen/jit.gl.pix's first inlet. So if you are sending the "jit.bfg 3 float32 10 10 10" to the first inlet, then cell, norm etc. will be 3-element vectors. You can pull out individual elements (dims) of the vector using [swiz x], [swiz z] etc. (or [swiz 0], [swiz 2] etc.). And you can pack values into bigger vectors again using [vec] and [concat] operators.