A new device for measuring spatial reflectance distributions of surfaces and a new mathematical model of anisotropic reflectance are introduced. The model is simple and accurate, enabling efficient data reduction and reproduction. The device uses imaging technology to capture the entire hemisphere of reflected directions, significantly speeding up data collection. Example measurements and simulations are shown, along with a table of fitted parameters for several surfaces. The paper discusses the importance of accurate reflectance models in computer graphics, highlighting the limitations of existing empirical and theoretical models. It introduces the bidirectional reflectance distribution function (BRDF), which describes the interaction of light with a surface. A new imaging gonioreflectometer is presented, which allows for rapid and cost-effective measurement of BRDFs. The device uses a half-silvered hemisphere and a CCD camera to capture reflected light, enabling efficient data collection. The paper also presents a new anisotropic reflectance model based on an elliptical Gaussian function. This model is simple, physically meaningful, and can be fitted to measured data with few parameters. The model is tested on various surfaces, including varnished wood and unfinished aluminum, and is shown to accurately reproduce anisotropic reflectance properties. The paper discusses the challenges of rendering anisotropic surfaces in computer graphics, proposing a hybrid deterministic and stochastic ray tracing technique to balance accuracy and efficiency. The model is applied to real-world scenes, demonstrating its effectiveness in simulating anisotropic reflections. The paper concludes that while the initial efforts are promising, further investigation into empirical shading models is needed. The work highlights the importance of both theory and data in scientific research, emphasizing the need for accurate and efficient reflectance models in computer graphics.A new device for measuring spatial reflectance distributions of surfaces and a new mathematical model of anisotropic reflectance are introduced. The model is simple and accurate, enabling efficient data reduction and reproduction. The device uses imaging technology to capture the entire hemisphere of reflected directions, significantly speeding up data collection. Example measurements and simulations are shown, along with a table of fitted parameters for several surfaces. The paper discusses the importance of accurate reflectance models in computer graphics, highlighting the limitations of existing empirical and theoretical models. It introduces the bidirectional reflectance distribution function (BRDF), which describes the interaction of light with a surface. A new imaging gonioreflectometer is presented, which allows for rapid and cost-effective measurement of BRDFs. The device uses a half-silvered hemisphere and a CCD camera to capture reflected light, enabling efficient data collection. The paper also presents a new anisotropic reflectance model based on an elliptical Gaussian function. This model is simple, physically meaningful, and can be fitted to measured data with few parameters. The model is tested on various surfaces, including varnished wood and unfinished aluminum, and is shown to accurately reproduce anisotropic reflectance properties. The paper discusses the challenges of rendering anisotropic surfaces in computer graphics, proposing a hybrid deterministic and stochastic ray tracing technique to balance accuracy and efficiency. The model is applied to real-world scenes, demonstrating its effectiveness in simulating anisotropic reflections. The paper concludes that while the initial efforts are promising, further investigation into empirical shading models is needed. The work highlights the importance of both theory and data in scientific research, emphasizing the need for accurate and efficient reflectance models in computer graphics.