Yes, people really do 3D CAD on Mobile devices!

I've been using OnShape https://www.onshape.com/ as my primary 3D modelling package for some time now - both for designing parts for my hobby 3D printing and laser cutting, and also for general work (engineering) applications.

You can check out my early quick review here: http://julianh72.blogspot.com.au/2015/08/affordable-free-3d-modelling-software-5.html - and the more I've used it, the more impressed I've been.

I use OnShape primarily via Chrome browser on a Windows laptop (work or home) or a Windows tablet or a Chromebook, but I also use it on my Android tablet (and it is also available for iPads). What surprises many people is that OnShape can truly be used for full-featured 3D modelling (not just viewing) on mobile devices.

OnShape have just released a blog post "YES, PEOPLE REALLY DO CAD ON MOBILE!" https://www.onshape.com/cad-blog/yes-people-users-really-do-cad-on-mobile?utm_source=hs_email&utm_medium=email&utm_content=29936753&_hsenc=p2ANqtz-_jJNrK2qf9-xSiJlTvoqBOoscIhi_lDT2Vjq5p3JUpel2rp7KPKmYUU2SwkCkRlqVDaBJJ5WUiwAwE5vgIpQKm9UIODA&_hsmi=29936753 which gives some actual statistics which demonstrate that people really are using OnShape Mobile for modelling and design, not just viewing. While browser use is an order of magnitude bigger than mobile use (as you would expect), it is interesting to note that the usage patterns mimic each other on both platforms, except on weekends and holiday periods, where mobile use sees proportionately less of a dip than browser use - indicating it is the "platform of choice" for many users when you are away from the office.

If you are looking for a capable low-cost (free!) 3D modelling package for your hobby use, you really need to check out OnShape, if you have not done so already!