Gumroad link - https://gumroad.com/products/PtkDM
This is an in-depth tutorial about designing a complicated robot inside 3DCoat. Starting from a rough 3D sketch towards a heavy posable assembly. Special attention is paid towards making proper joints for different parts of the model.
I've been using 3D Coat on an everyday basis for the last 2 years and I talk extensively about utilizing the software at its best being at the same time aware of the bugs and common issues.
Project files also include a promo code for my photo pack of an amazing Gundam Robot statue in Tokyo. It served as an original inspiration and reference for the tutorial.