I made those models using the only real 3D Modeler available for smartphones : Spacedraw. I worked more than 3 years with the the sole coder of this app, building more and more complex test scenes as I got used to the app, and writing lengthy bug reports and improvement suggestions. Working without any computer software was a real challenge (especially for the unwrapping part that I had to do basically quad by quad) and I understood a lot about the logic of what’s behind the hood of our everyday powerful 3D softs on PC.
It was a lot of fun modeling those meshes and discovering the truly impressive power hidden behind Spacedraw’s text based UI. Modeling, unwrapping (a nightmare, especially for the robot) and textures were all made with only a smartphone.
Sadly, Spacedraw is an abandoned project as the developer moved on to AI programming. Main reason being that if 3D modeling on smartphones felt for a while like an interesting niche, it sadly does not interest enough people yet.