Orthographic Projections, ContinuedIsometric scaleAn isometric scale measures foreshortened lines with uniform accuracy.Drawings made using an isometric scale create isometric projections byrendering the object exactly as seen on the plane of projection.You canmake an isometric scale on paper or cardboard to aid you in laying outmeasurements. All distances in an isometric scale are 2/3 times true lengthor approximately 80 percent of true size.To make an isometric scale, use this table:Step1ActionAlong a horizontal line, mark off equal increments with anystandard scale (figure 6-15, view A).2Using a 45° triangle, lay off lines from each of the increments.3Using a 45° and a 30°/60° triangles, form a 75° angle with thehorizontal and lay off a line intersecting the diagonal lines.4Align a piece of paper, acetate, or cardboard, with the 75° lineindicating equal increments. These increments form the isometricscale.Continued on next page6-18