I converted the .stl file to .jpg files, and inserted them as a sketch picture.
This way I can sketch lines and arcs according to the optimized design.
For such a complex part like optimized-upright, I can't use the basic-features in SolidWorks, so I decided to use surface-modelling.
This is a simplified version for parametric-upright. It is made by basic features in SW, such as extrude-cut, lofted-cut, and boundary-cut.
The mass is the same as previous one, but the shape is less in details.
If you want, I can give additional-fillets to this model.