13,669 research outputs found
The Iray Light Transport Simulation and Rendering System
While ray tracing has become increasingly common and path tracing is well
understood by now, a major challenge lies in crafting an easy-to-use and
efficient system implementing these technologies. Following a purely
physically-based paradigm while still allowing for artistic workflows, the Iray
light transport simulation and rendering system allows for rendering complex
scenes by the push of a button and thus makes accurate light transport
simulation widely available. In this document we discuss the challenges and
implementation choices that follow from our primary design decisions,
demonstrating that such a rendering system can be made a practical, scalable,
and efficient real-world application that has been adopted by various companies
across many fields and is in use by many industry professionals today
Path-tracing Monte Carlo Library for 3D Radiative Transfer in Highly Resolved Cloudy Atmospheres
Interactions between clouds and radiation are at the root of many
difficulties in numerically predicting future weather and climate and in
retrieving the state of the atmosphere from remote sensing observations. The
large range of issues related to these interactions, and in particular to
three-dimensional interactions, motivated the development of accurate radiative
tools able to compute all types of radiative metrics, from monochromatic, local
and directional observables, to integrated energetic quantities. In the
continuity of this community effort, we propose here an open-source library for
general use in Monte Carlo algorithms. This library is devoted to the
acceleration of path-tracing in complex data, typically high-resolution
large-domain grounds and clouds. The main algorithmic advances embedded in the
library are those related to the construction and traversal of hierarchical
grids accelerating the tracing of paths through heterogeneous fields in
null-collision (maximum cross-section) algorithms. We show that with these
hierarchical grids, the computing time is only weakly sensitivive to the
refinement of the volumetric data. The library is tested with a rendering
algorithm that produces synthetic images of cloud radiances. Two other examples
are given as illustrations, that are respectively used to analyse the
transmission of solar radiation under a cloud together with its sensitivity to
an optical parameter, and to assess a parametrization of 3D radiative effects
of clouds.Comment: Submitted to JAMES, revised and submitted again (this is v2
Effects of virtual acoustics on dynamic auditory distance perception
Sound propagation encompasses various acoustic phenomena including
reverberation. Current virtual acoustic methods, ranging from parametric
filters to physically-accurate solvers, can simulate reverberation with varying
degrees of fidelity. We investigate the effects of reverberant sounds generated
using different propagation algorithms on acoustic distance perception, i.e.,
how faraway humans perceive a sound source. In particular, we evaluate two
classes of methods for real-time sound propagation in dynamic scenes based on
parametric filters and ray tracing. Our study shows that the more accurate
method shows less distance compression as compared to the approximate,
filter-based method. This suggests that accurate reverberation in VR results in
a better reproduction of acoustic distances. We also quantify the levels of
distance compression introduced by different propagation methods in a virtual
environment.Comment: 8 Pages, 7 figure
Massively Parallel Ray Tracing Algorithm Using GPU
Ray tracing is a technique for generating an image by tracing the path of
light through pixels in an image plane and simulating the effects of
high-quality global illumination at a heavy computational cost. Because of the
high computation complexity, it can't reach the requirement of real-time
rendering. The emergence of many-core architectures, makes it possible to
reduce significantly the running time of ray tracing algorithm by employing the
powerful ability of floating point computation. In this paper, a new GPU
implementation and optimization of the ray tracing to accelerate the rendering
process is presented
Importance driven environment map sampling
In this paper we present an automatic and efficient method for supporting Image Based Lighting (IBL) for bidirectional methods which improves both the sampling of the environment, and the detection and sampling of important regions of the scene, such as windows and doors. These often have a small area proportional to that of the entire scene, so paths which pass through them are generated with a low probability. The method proposed in this paper improves this by taking into account view importance, and modifies the lighting distribution to use light transport information. This also automatically constructs a sampling distribution in locations which are relevant to the camera position, thereby improving sampling. Results are presented when our method is applied to bidirectional rendering techniques, in particular we show results for Bidirectional Path Tracing, Metropolis Light Transport and Progressive Photon Mapping. Efficiency results demonstrate speed up of orders of magnitude (depending on the rendering method used), when compared to other methods
- …