This study analyses one of the most popular game engines and an audio middleware to reproduce sound according to sound propagation physics. The analysis focuses on the transmission path between the ...sound source and the receiver. Even if there are several ready-to-use real-time auralization platforms and software, game engines' use with this aim is a recent study area for acousticians. However, audio design needs with game engines and the limits of their basic releases require additional tools (plugins and middleware) to improve both the quality and realism of sound in virtual environments. The paper discusses the use of Unreal Engine 4 and Wwise's 3D audio production methods in a set of different test environments. It assesses their performance in regard to a commercial geometrical acoustics software. The results show that the investigated version of the game engine and its sound assets are insufficient to simulate real-world cases and that significant improvements can be achieved with use of the middleware.
Functionally defined objects for realistic scenes are offered. We describe physically based visualization of three-dimensional objects based on perturbation functions; i.e., the rendering of ...materials occurs with regard to the laws of physics. Physically based reflection models are needed to obtain photorealistic images. The surface roughness, microrelief, and gloss suggest how smooth or rough the surface of the material is. The diffraction effects are shown taking into account the roughness of the surface. Subsurface light transport is considered and modeled using bidirectional surface scattering.
The Phong and Modified Phong specular BRDFs, although of limited physical basis, are nevertheless some of the simplest BRDFs exhibiting glossy and specular qualities to understand and to implement, ...making them useful for validation and teaching. Unfortunately, although it is well-known how to make these BRDFs
conserve
energy (that is, never gain energy), making them energy-
normalized
(that is, never lose nor gain energy) is far more difficult. Lesser-known algorithms exist, but require the specular exponent
n
to be integer-valued, and have
O
(
n
) runtime cost. We express these algorithms as mathematical formulae and generalize to the real-valued specular exponent case. We then simplify and optimize to finally attain an algorithm that is
O
(1). Energy normalization makes the Phong BRDFs more physically plausible and therefore both more practically and theoretically useful—and our improvements allow for this energy normalization to be done efficiently and without arbitrary limitations.
We present a method that estimates the physically accurate reflectance of materials from a single image and reproduces real world materials which can be used in well-known graphics engines and tools. ...Recovering the BRDF (bidirectional reflectance distribution function) from a single image is an ill-posed problem due to the insufficient irradiance and geometry information as well as the insufficient samples on the BRDF parameters. The problem could be alleviated with a simplified representation of the surface reflectance such as Phong reflection model. Recent works have appealed that convolutional neural network successfully predicts parameters of empirical BRDF models for non-Lambertian surfaces. However, parameters of the physically-based model confront the problem of having non-orthogonal space, making it difficult to estimate physically meaningful results. In this paper, we propose a method to estimate parameters of a physically-based BRDF model from a single image.We focus on the metallic property of the physically-based model to enhance the estimation accuracy. Since metals and nonmetals have very different characteristics, our method processes them separately. Our method also generates auxiliary maps using a cGAN (conditional generative adversarial network) architecture to help in estimating more accurate BRDF parameters. Based on the experimental results, the auxiliary map is selected as an irradiance environment map for the metallic and a specular map for the nonmetallic. These auxiliary maps help to clarify the contributions of different actors, including light color, material color, specular component, and diffuse component, to the surface color. Our method first estimates whether the material on the input image is metallic or nonmetallic. Then, it estimates BRDF parameters using CNN (convolutional neural networks) architecture guided by generated auxiliary maps. Our results show that our method is effective to estimate BRDF parameters both on synthesized as well as real images.
Rendering using physically based methods requires substantial computational resources. Most methods that are physically based use straightforward techniques that may excessively compute certain types ...of light transport, while ignoring more important ones. Importance sampling is an effective and commonly used technique to reduce variance in such methods. Most current approaches for physically based rendering based on Monte Carlo methods sample the BRDF and cosine term, but are unable to sample the indirect illumination as this is the term that is being computed. Knowledge of the incoming illumination can be especially useful in the case of hard to find light paths, such as caustics or scenes which rely primarily on indirect illumination. To facilitate the determination of such paths, we propose a caching scheme which stores important directions, and is analytically sampled to calculate important paths. Results show an improvement over BRDF sampling and similar illumination importance sampling.
Rendering using physically based methods requires substantial computational resources. Most methods that are physically based use straightforward techniques that may excessively compute certain types of light transport, while ignoring more important ones. Importance sampling is an effective and commonly used technique to reduce variance in such methods. Most current approaches for physically based rendering based on Monte Carlo methods sample the BRDF and cosine term, but are unable to sample the indirect illumination as this is the term that is being computed. Knowledge of the incoming illumination can be especially useful in the case of hard to find light paths, such as caustics or scenes which rely primarily on indirect illumination. To facilitate the determination of such paths, we propose a caching scheme which stores important directions, and is analytically sampled to calculate important paths.
We describe a technique for interactive rendering of diffraction effects produced by biological nanostructures, such as snake skin surface gratings. Our approach uses imagery from atomic force ...microscopy that accurately captures the geometry of the nanostructures responsible for structural colouration, that is, colouration due to wave interference, in a variety of animals. We develop a rendering technique that constructs bidirectional reflection distribution functions (BRDFs) directly from the measured data and leverages pre‐computation to achieve interactive performance. We demonstrate results of our approach using various shapes of the surface grating nanostructures. Finally, we evaluate the accuracy of our pre‐computation‐based technique and compare to a reference BRDF construction technique
We describe a technique for interactive rendering of diffraction effects produced by biological nanostructures, such as snake skin surface gratings. Our approach directly uses imagery from atomic force microscopy that accurately captures the geometry of the nanostructures responsible for structural colouration, that is, colouration due to wave interference, in a variety of animals.
Checking the irreversible process of clean-up is a delicate task that requires a work of synthesis between theoretical knowledge and practical experience, to define an effective operating protocol on ...a limited patch area to be extended later to the entire artefact’s surface. In this paper, we present a new, quick, semi-automated 3D photogrammetry-based solution to support restorers in the open-air bronze artwork cleaning from corrosion and weathering decay. The solution allows the conservators to assess in real time and with a high level of fidelity in colour and shape, the ‘surfaces’ to be cleaned before, during and after the clear-out treatment. The solution besides allows an effective and valuable support tool for restorers to identify the original layer of the bronze surface, developed and validated during the ongoing restoration of the Neptune Fountain in Bologna.
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