TinkerCAD is a great, beginner-friendly software. However, it's limited in functionality, so I had to switch to SelfCAD.

Slicing software needs to maintain a balance between ease-of-use and control, while handling handle any STL file you throw at it. If you eliminate the need to convert an existing 3D model ...

When slicing a model for 3D printing, the part is divided into a stack of flat, 2D layers. But there’s an alternative in the form of non-planar slicing, where the layers can follow 3D curves.