b'Figure 4. Visualization of the variable extensometer to a macroscale experiment a) initial reference image to obtain initial gauge lengths only three of the thousands of extensometers are shown for clarity b) increasing displacement of the virtual extensometers as axial strain accumulates, c) final image captured before failure used to calculate the final elongation of each extensometer. Note the onset of necking near the middle of the gauge section d) the virtual extensometers that do not span the necking region are used to calculate the uniform specimen elongation. e-g) Comparison of the point clouds obtained across nine macroscale ductility experiments conducted on copper. Red point clouds are for specimens with a gauge length of 40mm, green is for 60mm gauge length specimens, and blue is for 80 mm gauge length specimens2022|AFC ACCOMPLISHMENTS 51'