The solid modeling method is typically used when modeling with solid features. The following are key features of the solid modeling approach:

• It is characterized by 2D sketches/profiles used in creating extrusions, revolutions, and lofts to form solids, and blends on the edges of solids.

  

• It most often involves the addition or subtraction of material using analytic shapes.

• The model's topology is driven by faces.

• Holes are used for alignment.

• Feature faces are used for alignment as well as for mating with other features.

• Edges are rounded for safety and strength.

• Edges and faces are primarily analytic-based.

Modeling with surface-based features typically begins with a wireframe, from which surfaces are generated. Key features of surface modeling:

• It is characterized by control points used to define 2D and 3D curves.

• A model's topology is driven by edges and curves. Edges and faces are mainly based on splines.

  

• Surface shapes are very important, therefore direct editability of underlying curves and edges is crucial.

• Highlight lines, silhouette edges and flow lines of a model are important.