Hi Adam,
Sorry, I wasn't clear in my question. I have x,y,z data and I want to convert them to observation points but Feflow asks for slice number. However, I do not know that for my points. And it seems like when I don't include slice number and choose "free x,y,z" it does not give me and error bar when I run the model. I don't know if the two are related but my suspicion is that Feflow requires slice numbers. So the question is how do I extract slice number for an x,y,z point?