# GPU Ray Tracing for the Analysis of Light Deflection in Inhomogeneous Refractive Index Fields of Hot Tailored Forming Components

## TL;DR

This paper uses GPU ray tracing to study how light bends in hot forming processes, helping improve quality monitoring by predicting optical distortions.

## Contribution

The novel use of GPU-accelerated ray tracing to analyze light deflection in inhomogeneous refractive index fields during hot-forming.

## Key findings

- GPU ray tracing effectively simulates light deflection in inhomogeneous refractive index fields.
- Simulation results help optimize measurement positions to reduce uncertainties in optical geometry reconstruction.
- The method improves the reliability of quality control in hot-forming processes.

## Abstract

In hot-forming, integrating in situ quality monitoring is essential for the early detection of thermally induced geometric deviations, especially in the production of hybrid bulk metal parts. Although hybrid components are key to meeting modern technical requirements and saving resources, they exhibit complex shrinkage behavior due to differing thermal expansion coefficients. During forming, these components are exposed to considerable temperature gradients, which result in density fluctuations in the ambient air. These fluctuations create an inhomogeneous refractive index field (IRIF), which significantly affects the accuracy of optical geometry reconstruction systems due to light deflection. This study utilizes existing simulation IRIF data to predict the magnitude and orientation of refractive index fluctuations. A light deflection simulation run on a GPU-accelerated ray tracing framework is used to assess the impact of IRIFs on optical measurements. The results of this simulation are used as a basis for selecting optimized measurement positions, reducing and quantifying uncertainties in surface reconstruction, and, therefore, improving the reliability of quality control in hot-forming applications.