I am a high school teacher who teachers tech ed and am looking to incorporate 3D printing into some of my classes. All the students were each given their own Ipad's this year so I am trying to use with 3d printer them instead of having to spend any extra money on computers and Solidworks for my classroom.

What would you recommend that I use to have the students to design their projects in on their Ipad? I want something that will be on the easier side for them to learn the basics of how to use but still have the technical capabilities to allow them to make something technical and complex?
I've seems their are quite a few options, but I don't have the time to try them all. Any input would be appreciated!