Professional Drafting Scales, Engineer Scales, and Architect Scales in various sizes and models. The classic triangular scale is still very popular with users today which comes in engineers, architects, or metric scales. Even if rely on CAD, a scale can be very handy for taking measurements off of scaled drawings. Triangular Scales are great to take along in your briefcase as well as your vehicle since you never know when you'll need to use one. Architect Scales are easy to read, you move the nearest foot to the line of what you are measuring, then read the inches on the other end of the scale. Most common Architect scales would be 1/4" = 1'-0", or 1/8" = 1'-0". Most common Engineer scales would be 1:20, 1:50, or 1:100. The scale at which your drawing is drawn or printed decides which scale you will need to scale off the drawings when measuring distance. Of course, a drawing or map not drawn to scale proposes a problem when trying to measure at scale, so it's important to discover what your drawing or map is drawn or printed at before reaching for a scale. You might even call it a "Ruler" but your Drafting Instructor would want you to call it a "Scale" instead.