Which feature is used to create a 3D solid from a 2D sketch in SolidWorks?

The feature that generates a 3D solid from a 2D sketch in SolidWorks is the Extrude Boss/Base function. This feature allows users to take a 2D sketch and extend it in a straight line along a defined direction, effectively adding depth to the sketch and forming a three-dimensional object.

When you create an extrusion, you start with a flat profile represented by your sketch and apply a specified thickness or depth to it. This is fundamental in solid modeling, as it serves as the primary method for turning sketches into 3D forms. The ability to choose the extrusion depth or to extrude to a certain face or surface makes it versatile for creating various geometries.

In contrast to other features mentioned, such as the Revolve Boss/Base, which generates a solid by rotating a sketch around an axis, and the Loft Boss/Base, which connects multiple profiles to create complex forms, the Extrude Boss/Base is often the first feature learned since it's straightforward and applicable to a wide variety of design scenarios. Shell creates a hollowed-out version of an object rather than forming new solid geometry, further highlighting the distinct purpose of the Extrude Boss/Base in solid modeling.