It is desirable for endovascular surgery simulation to describe with quantitative data the interaction between the catheter and the blood vessel model wall to make an objective evaluation of the procedure. Photoelastic stress analysis in straight segments of multi-layered models was used for that purpose. In this research we study the error introduced by stress direction on the magnitude measurements, for photoelastic stress analysis. And we propose a scanner for three dimensional visualization of photoelastic stress analysis. As result, we quantified that the maximum contribution of error from stress direction in the first half of the fringe is 2.52% for the stress magnitude measurements. Three-dimensional stress visualization was obtained in segment of straight vasculature with an average error in sample slices of 10.73%, 4.55% and 3.18% for inner pressures of 80, 120 and 160mmHg respectively.