pixel mapping chauvet nexus 4x4 via artnet

I have a student who is programming 9 x nexus panels 4 x 4 with Millumin via artnet. I am wondering if there is a way to change the pixel layout at all like in Madmapper? At the moment, things go left to right but up and down is the wrong way round. I feel I'm missing something basic here!

Thanks,

Ben