But, I expect my kid will have moved on to some other thing by then. probably learn a lot about Meshmixer by the time I'm done. I suppose I could go through and fix every one of those pink spheres.

not saying that's the right choice for everyone. I don't mind learning, but given a choice it would be Meshmixer over Blender. Meshmixer seems a lot more in line with how I think. I expect Blender is a wonderful and powerful program, but the interface. I get the same results via OBJ or STL import. Ha! 300 odd pink balls with lines, bunch of blue ones, some red as well. So, I learned about Analysis and Inspector. Got my head wrapped around it, got it to do a cut, but when I went to separate shells. I like Fusion 360, so, I thought I'd try Meshmixer. Anyway, I can get Blender to export it to an OBJ or STL, and I can open the OBJ or STL in Cura and slice it without issue, except I would rather make a few changes and break it into pieces so I can print it bigger. (A DH88, like Bulldog in the the Planes movie if your curious). I have this model, a Blender file, and I want to 3Dprint it for my kid.

Blender stl