Low Poly geometry

A friend of mine gave me a stl file he wanted me to print.
He made it in blender and it has no mass, just geometry (thin walls)
I was asked to make it 3d printable.
But sinc I only can use the STL file as reference I was struggling to recreate the geometry in Shapr3d .

I can’t show it since it’s for a client of his. But this climbing wall has basically the same issue. Low poly model built up by flat geometric shapes.
How would you make something like this in Shapr3d? If not optimal, what other tool would you use (on ipad) ? Is Nomad a better fit for this? (I’m not good at using Nomad though)

I think shapr is not the best tool for this, I would try blender or something with more mesh modelling tools.