23 research outputs found
Patterns and dynamics of neutral lipid fatty acids in ants – implications for ecological studies
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Simple Nested Dielectrics in Ray Traced Images
This paper presents a simple method for modeling and rendering refractive objects that are nested within each other. The technique allows the use of simpler scene geometry and can even improve rendering time in some images. The algorithm can be easily added into an existing ray tracer and makes no assumptions about the drawing primitives that have been implemented
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Caustic Forecasting: Unbiased Estimation of Caustic Lighting for Global Illumination
We present an unbiased method for generating caustic lighting using importance sampled Path Tracing with {\em Caustic Forecasting}. Our technique is part of a straightforward rendering scheme which extends the \emph{Illumination by Weak Singularities} method to allow for fully unbiased global illumination with rapid convergence. A photon shooting preprocess, similar to that used in Photon Mapping, generates photons that interact with specular geometry. These photons are then clustered, effectively dividing the scene into regions which will contribute similar amounts of caustic lighting to the image. Finally, the photons are stored into spatial data structures associated with each cluster, and the clusters themselves are organized into a spatial data structure for fast searching. During rendering we use clusters to decide the caustic energy importance of a region, and use the local photons to aid in importance sampling, effectively reducing the number of samples required to capture caustic lighting
Caustic Forecasting: Unbiased Estimation of Caustic Lighting for Global Illumination
We present an unbiased method for generating caustic lighting using importance sampled Path Tracing with {\em Caustic Forecasting}. Our technique is part of a straightforward rendering scheme which extends the \emph{Illumination by Weak Singularities} method to allow for fully unbiased global illumination with rapid convergence. A photon shooting preprocess, similar to that used in Photon Mapping, generates photons that interact with specular geometry. These photons are then clustered, effectively dividing the scene into regions which will contribute similar amounts of caustic lighting to the image. Finally, the photons are stored into spatial data structures associated with each cluster, and the clusters themselves are organized into a spatial data structure for fast searching. During rendering we use clusters to decide the caustic energy importance of a region, and use the local photons to aid in importance sampling, effectively reducing the number of samples required to capture caustic lighting
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Shell Maps
A shell map is a bijective mapping between shell space and texture space that can be used to generate small-scale features on surfaces using a variety of modeling techniques. The method is based upon the generation of an offset surface and the construction of a tetrahedral mesh that fills the space between the base surface and its offset. By identifying a corresponding tetrahedral mesh in texture space, the shell map can be implemented through a straightforward barycentriccoordinate map between corresponding tetrahedra. The generality of shell maps allows texture space to contain geometric objects, procedural volume textures, scalar fields, or other shell-mapped objects
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An Ocularist's Approach to Human Iris Synthesis
Human irises gain their appearance from a layered and highly complex structure that is difficult to model and render with conventional techniques. We present an approach that uses domain knowledge from the field of ocular prosthetics. In that field, ocularists create an artificial iris by painting many simple semi-transparent layers. We translate this methodology into a simple and effective toolkit which can be used to create and render realistic looking irises
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Dense Geometric Flow Visualization
We present a flow visualization technique based on rendering geometry in a dense, uniform distribution. Flow is integrated using particle advection. By adopting ideas from texture-based techniques and taking advantage of parallelism and programmability of contemporary graphics hardware, we generate streamlines and pathlines addressing both steady and unsteady flow. Pipelining is used to manage seeding, advection, and expiration of streamlines/pathlines with constant lifetime. We achieve high numerical accuracy by enforcing short particle lifetimes and employing a fourth-order integration method. The occlusion problem inherent to dense volumetric representations is addressed by applying multi-dimensional transfer functions (MDTFs), restricting particle attenuation to regions of certain physical behavior, or features. Geometry is rendered in graphics hardware using techniques such as depth sorting, illumination, haloing, flow orientation, and depth-based color attenuation to enhance visual perception. We achieve dense geometric three-dimensional flow visualization with interactive frame rates