In this communication an almost forgotten topic in mechanics will be revisited: the utilisation of stress trajectories, also known as isostatic lines, to visualise stress states. This is motivated by the recent publication of a paper on the topic, where the practical implementation of the process of drafting stress trajectories in 2D and 3D domains is discussed, in particular at the points where the principal directions are not uniquely defined. The aforementioned work considers very briefly the relevance of the quality of approximate solutions, typically finite element based, on the stress trajectories. This presentation at the ADMOS conference will provide a more detailed assessment of the influence of the solution error on the stress trajectories that are obtained.