A Virtual Goniometer (VIRGO) to predict the directional and random incidence diffusion and scattering coefficients from a Computer-Aided Design file

Experimental determination of scattering and diffusion coefficients in accordance with ISO 17497-1 and ISO 17497-2 is a time-consuming process and not commonly offered by commercial laboratories. These methods require multiple physical samples, access to an anechoic or large reflection-free environment, and far-field measurement conditions. To overcome these limitations, a Virtual Goniometer based on wave-based numerical techniques is employed to accurately predict diffusion coefficients. This eliminates the need for fabricating scale models or full-scale prototypes for experimental testing. The approach uses a Finite Element Method combined with a Perfectly Matched Layer to simulate free-field conditions and compute diffusion coefficients directly from a 3-D Computer-Aided Design geometry. This strategy enables accurate modeling of complex topologies and supports region-specific frequency-dependent fluid properties, facilitating simulations based on equivalent-fluid models. It calculates both directional and random-incidence diffusion coefficients as defined by ISO 17497-2 and extends the analysis to directional and random-incidence correlation scattering coefficients for any arbitrary geometry. This technique greatly streamlines the design evaluation process by enabling rapid virtual testing of commercial products and custom architectural surface designs, significantly reducing time and resource demands. Representative examples will be presented.