Hi everyone, I'm trying to draw a stress-strain curve with data collected from the test itself. I have no problem plotting the points obtained, but I can't figure out how to graphically or at least with some kind of software aid, to get results (σ0.2, σmax, σ0.5, and so on). I tryed with excel, but even though I can draw lines on the graphic by hand, it's not the most precise thing. Also with octave, but drawing aditional lines over the curve involves interpolation and it's lots of work for just a few lines. Does somebody have an "easy" solution for this? cheers!