A comparison of traditional casting techniques with current 3D scanning methods

For decades, shoe and tire impression marks have been preserved primarily using plaster or sulfur casts. While the composition of materials used in plaster casts has evolved—particularly toward dental plasters that reproduce details with high precision—a persistent concern remains in the minds of many users: Especially at temperatures at around +4°C (39°F) and below, the long setting time supposedly extends the time spent at the crime scene. Due to time constraints, plaster casts are therefore often omitted, and the scene is merely documented photographically, which severely limits the possibilities for unambiguous attribution or reliable exclusion of a trace to a specific shoe. The article describes the testing of a dental plaster used in forensic evidence collection under various temperature conditions. In addition, alternative, non-contact methods such as 3D scanning and photogrammetry are tested and finally compared with the results of traditional plaster casts to determine whether current digital 3D scanning methods are suitable as reliable comparison methods.