Layer guide option grayed out when creating Modflow model from GM

RohitWarrier

I'm trying to create a new modflow model from my geologic model with 6 layers but the "select layer guide" option appears grayed out. Why is that and how can I correct it so I can select all layers, not just the top and bottom of the model?

RohitWarrier

Thanks to @Sean Buchanan for pointing out that the layers I built in the GM were intrusions, which are considered unstructured grids and not yet supported in leapfrog for flow models.