Which feature allows a 2D sketch to be transformed into a 3D model or body?

The process of transforming a 2D sketch into a 3D model is primarily accomplished through the feature known as extrusion. When a sketch is extruded, it is extended in a perpendicular direction to create a solid body from the 2D profile. This is a foundational technique in 3D modeling that allows designers to define the height or depth of the object based on the 2D geometry they have created.

Extrusion is versatile and can be adjusted to create various features, such as adding material or even removing it through processes like negative extrusion. It provides the essential step in converting the flat representation of a design into a three-dimensional solid that can be further manipulated or refined.

The other options relate to different aspects of design and modeling but do not directly signify the process of converting a 2D sketch into a 3D shape. For instance, a fillet is used to create rounded edges but does not create a body from a sketch, and engineering drawing refers to the representation of a design on paper, which doesn't involve the 3D modeling aspect directly. The term feature is too generic in this context and does not specifically denote the action of creating a 3D model from a 2D sketch.