A comparative study between FARO Scene and FARO Zone 3D for area of origin analysis

Abstract

This comparative study aimed to investigate the differences between the workflow, accuracy, and reproducibility of the area of origin tools in FARO Scene and FARO Zone 3D software. Released in 2018, FZ3D has recently been introduced as an alternative application to FARO Scene’s Forensic Wizard plug-in for bloodstain pattern analysis but no accuracy studies have been published at the time of this study. A total of 15 impacts were created using an impact rig at three different positions from two orthogonal walls (50cm, 75cm, 100cm). One researcher conducted the analyses with both software packages, and the total errors using FZ3D were not statistically greater than using FARO Scene (p>0.05). With FZ3D, 50% of the total errors ranged from 6.63cm to 15.68cm with a minimum of 2.45cm, maximum of 27cm, and median of 11.22cm. With FARO Scene, 50% of the total errors ranged from 3.6cm to 15.5cm with a minimum of 2.93cm, maximum of 31.25cm and median of 9.6cm. A blind test with seven participants analyzing the same 15 impacts in FZ3D resulted in 100 out of 105 total errors (95%) to be within the accepted error range of 20cm. Of the five total errors outside 20cm, one was obtained from the 75cm position and four from the 100cm position. 75% of the total errors were below 9.43cm from the 50cm position, 14.88cm from the 75cm position, and 17.39cm from the 100cm position. This could indicate that there is a positive correlation between the distance of the impact from the surfaces and total errors obtained. Based on results of previous literature and comparison to FARO Scene software, FZ3D is shown to have acceptable area of origin analysis tools.