How does a profile of a surface tolerance relate to form and orientation?

• A. It controls only the size of a hole.
• B. It determines the surface finish requirements.
• C. It has no effect on orientation.
• D. It can control the form (shape) and orientation of the surface boundary as specified in the frame.

Answer: (D)

In GD&T, the profile of a surface tolerance creates a geometric envelope that the actual surface must lie within, and this envelope is defined in a frame of reference tied to datums. Because of that, it directly controls how the surface can deviate in shape (the form) and how the surface boundary can be oriented relative to those datums (the orientation). In other words, the profile tolerance sets limits on both the curvature and layout of the surface with respect to the reference frame, ensuring the part’s surface has the intended shape and tilt as specified.

This isn’t about hole size or surface roughness. It doesn’t imply no effect on orientation—quite the opposite: it constrains the surface boundary’s orientation as part of the profile envelope. So the ability to influence both form and orientation within the frame is what makes this the best choice.