Reference dimensions for radius measurement

Silhouette lines are not contour lines

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Finding contour lines on round parts when dimensioning in an ICD drawing can sometimes be challenging. This is mainly because the line type you are trying to find is not a sharp geometric contour line (even though that is what you "see" on the drawing), but rather a silhouette line—meaning the outer edge of a round bar. To dimension its ends, you may sometimes need to use a reference dimension from the radius center of a circle or circular arc. Watch our video above, which explains this and also provides a few helpful tips and tricks.

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