In terms of design for AM, what is meant by 'overhang'?

In the context of additive manufacturing design, 'overhang' specifically refers to a feature that hangs down without support, which is accurately captured by the selected response. Overhangs are critical in additive manufacturing because they present unique challenges during the printing process. Since the additive manufacturing process typically builds parts layer by layer from the bottom up, any part of a structure that extends beyond the layer below it without adequate support can lead to structural integrity issues.

This phenomenon is significant because overhangs can result in sagging or failure during the printing process, as the material may not adhere properly without something beneath it to anchor it. Understanding the nature of overhangs helps designers create parts that can be successfully printed, whether that involves adding supports or redesigning the geometry to minimize unsupported areas.

While the other options touch on aspects of design or manufacturing, they do not specifically define what is meant by 'overhang' in the same manner. A feature that extends horizontally, a layer that juts out, or material waste do not encapsulate the critical idea of features that require support when printed, which is the essence of an overhang in additive manufacturing.