Re: Lego and origami
In my case, Meccano, rather than Lego was my starting point, rapidly followed by balsa, glue, model aircraft kits and then building from plans.
Ever since I began to design my own flying models and (briefly *) flew RC models I've been able to visualise new models in 3D before I designed and built them. That's both complete models and partial assemblies. This ability has vastly helped in designing lots of stuff, not just new model aircraft.
* I quickly realised that, for me anyway, flying my own free flight designs in competitions was much more fun than driving RC models round the sky. Better exercise too, since you get to chase and retrieve your model after every flight.