Which command is used to extrude a solid object in modeling?

The command used to extrude a solid object in modeling is the "Extrude" command, which typically allows you to create a three-dimensional solid by extending a two-dimensional sketch in a straight line along a specified direction. This operation is fundamental in solid modeling as it transforms a 2D profile into a 3D object by adding depth.

When looking at the other options:

• Loft is utilized to create a solid by blending multiple cross-sections along a defined path, which is different from simply extending a shape.
• Revolve is used to create a solid by rotating a 2D sketch around a specified axis, thus forming a symmetrical shape rather than directly extruding.
• The extrude cut command is specifically for cutting material from existing solids rather than creating new volume.

Therefore, the extrude command is distinctly focused on producing solid volumes from sketches, making it the key operation for extrusion in solid modeling.