286 Geometric Dimensioning and Tolerancing Copyright Goodheart-Willcox Co., Inc. The feature control frame in Example 7-4 is placed with the diameter dimension. Remember, this placement associates the related geometric tolerance(s) with the fea- ture of size. The hole is a feature of size, which allows for a material condition modi- fier to be used. In this example, no material condition modifier is included next to the parallelism tolerance in the feature control frame, so RFS is the default. The specified positional tolerance applies at MMC. Parallelism can also be applied to control a feature axis relative to the axis of another feature when a parallel relationship between the features is desired. This con- trol establishes a cylindrical tolerance zone parallel to a datum axis. The axis of the controlled feature must lie within the tolerance zone. The cylindrical tolerance zone is indicated by placing a diameter symbol before the tolerance value in the feature control frame. RFS is the default unless MMC or LMC is applied. Example 7-5 shows a RFS application and Example 7-6 shows a MMC application. Parallelism of Line Elements Orientation tolerances applied to control a surface are implied to be total where all elements of the surface must fall within the specified tolerance zone. Where it is desir- able to control only individual line elements, rather than the entire surface, the note EACH ELEMENT is placed below the feature control frame, as shown in Example 7-7. This allows control of individual elements of the surface independently relative to the datum and does not control the entire surface within the tolerance zone.