I’m trying to rotate the grid from ‘black’ to ‘blue’. Not sure what defines the grid directions. I’ve tested with different surfaces and found the GH definition adapt differently to different surfaces… I would like to add components that can switch the direction of paneling easily…
Check the Wombat plugin for Grasshopper. It has a surface direction component where you can flip U and V or the direction of either of them. I just tried it with your file and it works fine.