I am trying to run particle tracking on modflow 6 model that has a unstructued grid (DISV package). When i run the modpath7 for it. It runs smoothly but when i want to define zones, it gives error and ask for a 3d array (layer, row, col). First, I thought that modpath7 is not recognizing that its an unstructured grid but then I checked the type of data allowed in defining zones in flopy.modpath.mp7sim module and i understood that there is no option for unstructured grid array, i.e 2d array of (layer, nodes) .

I would really like if someone can explain if there is something that i am understanding wrong, or there is another way to put zones and stopzones in modpath7 which i am unaware of.