Being able to draw from imagination and rotate objects really just comes down to how well you understand form and perspective. What you want to do is break the object down into simpler shapes that you can rotate and manipulate. Then you can combine those shapes. I see your putting a lot of effort into understanding the proportions. Proportions are important but they’re not as important as form. If you can learn to draw with form in perspective it becomes easier to then apply proportions. | Artwod Feedback