What Synchronous Modeling command is used to add or remove material from an area of a model?

The Synchronous Modeling command that is used to add or remove material from an area of a model is the Offset Region command. This command allows users to create new geometry by offsetting existing faces or regions. When you offset a region, you can specify a distance, which determines how much material is added, or you can use it to create a cut that removes material in that region. It adapts well to modifying the model without the need for traditional sketch-based features, offering greater flexibility in design changes.

In contrast, commands like Replace Face, Resize Face, and Thicken Face serve different roles in model manipulation. Replace Face is used to substitute one face with another, while Resize Face modifies the size of an existing face but does not directly add or remove material. Thicken Face implies creating a solid feature from a surface but is not specifically for removing or adding material in the way that Offset Region can. Thus, the Offset Region command stands out as the most appropriate choice for the task of modifying material within a specified area of the model.