Procedural Texture Research Articles

Multiple-process procedural texture

Our newly developed generation of procedural textures (GPT) system automatically generates procedural textures for the computer graphics industry. The system makes use of hybrid parallel Monte Carlo tree search and gender-based genetic algorithm modules that share a common multiple-generation population of procedural textures and a knowledge database. It also uses a multi-objective fitness function. The parallel Monte Carlo tree search module was inspired by gaming algorithms. To speed up the search, this module is enhanced with knowledge from previous successfully created procedural textures or tree node analyses. The gender-based genetic algorithm module automatically simulates several key features in natural selection and uses a multiple-generation breeding population, the notion of gender, and the concept of aging. This maintains diversity while providing many breeding opportunities for highly successful offspring. A third module selects generated shaders from the multiple-generation population and mutates them by replacing nodes with subtrees using the knowledge database. We evaluated the fitness quality of each module and compared the fitness quality of the system running in both single- and multiple-process mode. The optimal fitness quality was achieved by executing the system in multiple-process mode using a hybrid of these modules. We give examples of the GPT running in interactive mode, where a user directs the search towards the desired look using an esthetic evaluation.

Procedural voronoi foams for additive manufacturing

Microstructures at the scale of tens of microns change the physical properties of objects, making them lighter or more flexible. While traditionally difficult to produce, additive manufacturing now lets us physically realize such microstructures at low cost. In this paper we propose to study procedural, aperiodic microstructures inspired by Voronoi open-cell foams. The absence of regularity affords for a simple approach to grade the foam geometry --- and thus its mechanical properties --- within a target object and its surface. Rather than requiring a global optimization process, the microstructures are directly generated to exhibit a specified elastic behavior. The implicit evaluation is akin to procedural textures in computer graphics, and locally adapts to follow the elasticity field. This allows very detailed structures to be generated in large objects without having to explicitly produce a full representation --- mesh or voxels --- of the complete object: the structures are added on the fly, just before each object slice is manufactured. We study the elastic behavior of the microstructures and provide a complete description of the procedure generating them. We explain how to determine the geometric parameters of the microstructures from a target elasticity, and evaluate the result on printed samples. Finally, we apply our approach to the fabrication of objects with spatially varying elasticity, including the implicit modeling of a frame following the object surface and seamlessly connecting to the microstructures.

Evolving textures from high level descriptions

Evolutionary texture synthesis is used in a prototype tool intended to assist a designer or artist by automatically discovering collections of candidate textures to fit a given stylistic description. The textures used here are small colour images created by procedural texture synthesis. This paper describes four examples of stylistic description. Each is defined by a handwritten fitness function that rates how well a given texture meets this style. Genetic programming uses the fitness function to evolve programs written in a texture synthesis language. This system automatically generates a catalogue of variations on the given theme. A designer could then visually scan through these textures to pick out ones that seem aesthetically interesting. Their procedural 'genetic' representation would allow textures to be further adjusted by interactive evolution. The procedural representation also allows re-rendering textures at arbitrary pixel resolutions and provides a way to store them in a highly compressed form allowing lossless reconstruction.

Visual perception of procedural textures: identifying perceptual dimensions and predicting generation models.

Procedural models are widely used in computer graphics for generating realistic, natural-looking textures. However, these mathematical models are not perceptually meaningful, whereas the users, such as artists and designers, would prefer to make descriptions using intuitive and perceptual characteristics like "repetitive," "directional," "structured," and so on. To make up for this gap, we investigated the perceptual dimensions of textures generated by a collection of procedural models. Two psychophysical experiments were conducted: free-grouping and rating. We applied Hierarchical Cluster Analysis (HCA) and Singular Value Decomposition (SVD) to discover the perceptual features used by the observers in grouping similar textures. The results suggested that existing dimensions in literature cannot accommodate random textures. We therefore utilized isometric feature mapping (Isomap) to establish a three-dimensional perceptual texture space which better explains the features used by humans in texture similarity judgment. Finally, we proposed computational models to map perceptual features to the perceptual texture space, which can suggest a procedural model to produce textures according to user-defined perceptual scales.

Local random-phase noise for procedural texturing

Local random-phase noise is a noise model for procedural texturing. It is defined on a regular spatial grid by local noises, which are sums of cosines with random phase. Our model is versatile thanks to separate sampling in the spatial and spectral domains. Therefore, it encompasses Gabor noise and noise by Fourier series. A stratified spectral sampling allows for a faithful yet compact and efficient reproduction of an arbitrary power spectrum. Noise by example is therefore obtained faster than state-of-the-art techniques. As a second contribution we address texture by example and generate not only Gaussian patterns but also structured features present in the input. This is achieved by fixing the phase on some part of the spectrum. Generated textures are continuous and non-repetitive. Results show unprecedented framerates and a flexible visual result: users can control with one parameter the blending between noise by example and structured texture synthesis.

기하적 메쉬를 이용한 왕관형 수면 애니메이션을 구현하기 위한 효율적 방법

본 논문의 목적은 효율적인 왕관형 수면 애니메이션 제작 기법을 제안하는 것이다. 왕관형 수면 애니메이션을 제작하는 단계에서 비용과 시간이 많이 소요되는 문제가 있다. 이와 같은 문제점을 해결하기 위하여 기하적 메쉬와 절차적 텍스쳐를 활용한 물리기반 시뮬레이션이 필요 없는 왕관형 수면 애니메이션 기법을 제안한다. 텍스쳐는 메쉬에 적용하였고 적용된 데이터를 언리얼 엔진을 활용하여 재질을 제작한 뒤, 수면의 움직임을 제어 하였다. 그 결과 기존 유체 시뮬레이션 방법에 비해 빠른 시간에 사실적인 왕관형 수면 애니메이션을 만드는 것을 확인할 수 있었다. The paper provides an efficient method for generating water crown animation. Compared to general liquid simulation, water crown animation requires tremendous computational loads. Tackling the problem, we propose a novel geometry based approach with procedural texture. Unreal engine is utilized to construct material and handle the geometric mesh combined with water texture. The experimental results demonstrate our method achieves effective performance for realistic water crown animation.

Interactive Parameter Retrieval for Two‐Tone Procedural Textures

AbstractThe choice of parameters for procedural textures to achieve a desired appearance poses a challenging problem even for experienced artists. We propose a method to automatically determine such parameters to reproduce the appearance of input images. Addressing two‐tone textures, we separate the estimation of color and structure information and interpret the problem as image retrieval task from the space of procedural outputs. Applying a perceptually motivated image metric based on a texture descriptor enables us to precompute a comprehensive collection of possible parameter sets and yet achieve interactive retrieval performance. Our method supports a large variety of procedural texture models with a unified approach.

Efficient texture synthesis of aggregate solid material

Solid texturing is particularly well suited for many architectural materials as they are intrinsically 3D such as marbles and stones. Directly applying 2D texture to such material results in evident artifact because of the issue of synthesizing solid material or patterns usually very difficult. We propose the simple and effective solid synthesis that efficiently utilizes the procedural texture and exemplar-based synthesis seamlessly in one system. Our method generates warping particles and stores them with a few points based on cellular texture. Stereological technique and spring system are used to automatically guide the synthesis procedure. Using adaptive k-means clustering, we can recover color exemplar with high fidelity. We develop vector-represented results to avoid blurring, and GPU-based rendering for real-time synthesis on a common graphics card. Our experiments showed that the proposed approach can generate realistic texturing of solid material with low memory footprint and efficient aggregate-material synthesis in seconds.

Real-time Multiresolution Rendering for Dynamic Terrain

This paper presents a novel dynamic terrain multiresolution rendering method by utilizing the capabilities of current generation GPUs. Firstly, the terrain depth offset map texture that represents the appropriate offset values is generated through rendering to texture, which is used to deform terrain in vertex shader. Then in order to accurately represent the fine terrain detail created by deformation, an adaptive geometry tessellation technique is implemented in geometry shader. Moreover, to update deformation area texture, we apply procedural texturing based on constraint conditions in fragment shader. In the end, the experiments prove that our method is feasible and efficient.

Evolutionary Approach to Forex Expert Advisor Generation

We have developed a genetic algorithm approach for automatically generating expert advisors, computer programs that trade automatically in the financial markets. Our system, known as GenFx or Genetic Forex, evaluates evolutionarily generated expert advisors strategies using predetermined fitness functions to automatically prioritize parents for breeding. GenFx simulates several key factors in natural selection. It employs a multiple generation breeding population, a notion of gender, and the concept of aging to maintain diversity while providing many breeding opportunities to highly successful offspring. The approach is also especially efficient running in a multiple processor, multiple selection-strategy mode using multiple settings. We found out that a multi-processor gender-based running of the system outperformed all single runs of the system. This system is inspired by GenShade, a previous system that we have developed for evolutionary generating procedural textures. The methods described in this paper are not limited to the Forex market or financial problems only but are applicable to many other fields.

Texture synthesis using label assignment over a graph

Partition of unity parametrics (PUPs) are a recent framework designed for geometric modelling. We propose employing PUPs for procedural texture synthesis, taking advantage of the framework's guarantees of high continuity and local support. Using PUPs to interpolate among data values distributed through the plane, the problem of texture synthesis can be approached from the perspective of point placement and attribute assignment; a graph over the points, such as the Delaunay triangulation, allows us to apply attributes or labels to the nodes in a structured way. We present several alternative mechanisms for point distribution and demonstrate how the system is able to produce a variety of distinct classes of texture, including analogs to cellular texture, Perlin noise, and progressively-variant textures. We further describe structured textures obtained by assigning label clusters using queries over the graph, such as breadth-first or depth-first traversal.

A 3D CAMPUS INFORMATION SYSTEM – INITIAL STUDIES

Abstract. This paper discusses the method of developing Campus Information System. The system can handle 3D spatial data within desktop and web environment. The method consists of texturing of building facades for 3D building models and modeling 3D Campus Information System. In this paper, some of these steps are carried out; modelling 3D buildings, toggling these models on the terrain and ortho-photo, integration with a geo-database, transferring to the CityServer3D environment by using CityGML format and designing the service, etc. In addition to this, a simple but novel method of texturing of building façades for 3D city modeling that is based on Dynamic Pulse Function (DPF) is used for synthetic and procedural texturing. DPF is very fast compared to other photo realistic texturing methods. Last but not least, it is aimed to present this project on web using web mapping services. This makes 3D analysis easy for decision makers.

A Space Filling Algorithm for Generating Procedural Geometry and Texture

AbstractHere we present an algorithm for procedurally generating a range of digital assets including 2 dimensional textures and 2.5 dimensional texture roughness. The approach involves placing shapes randomly, without overlap and with a monotonically decreasing area, within a region on a plane (the 2 dimensional texture). If the process is continued to infinity then the result is space filling thus providing a variable and potentially infinite degree of visual detail. It will be proposed and illustrated that the process is independent of the actual shape being used and as such can find application to a range of texture effects. As a means of generating texture and form procedurally the result has the other desirable property of being fractal, that is, self similar across scales which is characteristic of many packings that occur in nature.

Stroke Parameterization

AbstractWe present a novel algorithm for generating a planar parameterization of the region surrounding a curve embedded in a 3D surface, which we call a stroke parameterization. The technique, which extends the well‐known Discrete Exponential Map [SGW06], uses the same basic geometric transformations and hence is both efficient and easy‐to‐implement. We also handle self‐intersecting curves, for which a 1–1 map between the original surface and the plane is not possible. Stroke parameterizations provide an ideal coordinate space for solving a variety of computer graphics problems. We present applications including tiling texture and displacement along 3D brush strokes, procedural texturing along 3D paths, and user‐guided crease extraction.

View‐Dependent Realtime Rendering of Procedural Facades with High Geometric Detail

AbstractWe present an algorithm for realtime rendering of large‐scale city models with procedurally generated facades. By using highly detailed assets like windows, doors, and decoration such city models can provide an extremely high geometric level of detail but on the downside they also consist of billions of polygons which makes it infeasible to even store them as explicit polygonal meshes. Moreover, when rendering urban scenes usually only a very small fraction of the city is actually visible which calls for effective culling mechanisms. For procedural textures there are efficient screen space techniques that evaluate, e.g., a split grammar on a per‐pixel basis in the fragment shader and thus render a textured facade in a view dependent manner. We take this idea further by introducing 3D geometric detail in addition to flat textures. Our approach is a two‐pass procedure that first renders a flat procedural facade. During rasterization the fragment shader triggers the instantiation of a detailed asset whenever a geometric facade element is potentially visible. The set of instantiated detail models are then rendered in a second pass. The major challenges arise from the fact that geometric details belonging to a facade can be visible even if the base polygon of the facade itself is not visible. Hence we propose measures to conservatively estimate visibility without introducing excessive redundancy. We further extend our technique by a simple level of detail mechanism that switches to baked textures (of the assets) depending on the distance to the camera. We demonstrate that our technique achieves realtime frame rates for large‐scale city models with massive detail on current commodity graphics hardware.

Multi‐scale Assemblage for Procedural Texturing

AbstractA procedural pattern generation process, called multi‐scale “assemblage” is introduced. An assemblage is defined as a multi‐scale composition of “multi‐variate” statistical figures, that can be kernel functions for defining noise‐like texture basis functions, or that can be patterns for defining structured procedural textures. This paper presents two main contributions: 1) a new procedural random point distribution function, that, unlike point jittering, allow us to take into account some spatial dependencies among figures and 2) a “multi‐variate” approach that, instead of defining finite sets of constant figures, allows us to generate nearly infinite variations of figures on‐the‐fly. For both, we use a “statistical shape model”, which is a representation of shape variations. Thanks to a direct GPU implementation, assemblage textures can be used to generate new classes of procedural textures for real‐time rendering by preserving all characteristics of usual procedural textures, namely: infinity, definition independency (provided the figures are also definition independent) and extreme compactness.

Procedural Texture Synthesis for Zoom‐Independent Visualization of Multivariate Data

AbstractSimultaneous visualization of multiple continuous data attributes in a single visualization is a task that is important for many application areas. Unsurprisingly, many methods have been proposed to solve this task. However, the behavior of such methods during the exploration stage, when the user tries to understand the data with panning and zooming, has not been given much attention.In this paper, we propose a method that uses procedural texture synthesis to create zoom‐independent visualizations of three scalar data attributes. The method is based on random‐phase Gabor noise, whose frequency is adapted for the visualization of the first data attribute. We ensure that the resulting texture frequency lies in the range that is perceived well by the human visual system at any zoom level. To enhance the perception of this attribute, we also apply a specially constructed transfer function that is based on statistical properties of the noise. Additionally, the transfer function is constructed in a way that it does not introduce any aliasing to the texture. We map the second attribute to the texture orientation. The third attribute is color coded and combined with the texture by modifying the value component of the HSV color model. The necessary contrast needed for texture and color perception was determined in a user study. In addition, we conducted a second user study that shows significant advantages of our method over current methods with similar goals. We believe that our method is an important step towards creating methods that not only succeed in visualizing multiple data attributes, but also adapt to the behavior of the user during the data exploration stage.

Procedural texture preview

AbstractProcedural textures usually require spending time testing parameters to realize the diversity of appearances.This paper introduces the idea of a procedural texture preview: A single static image summarizing in a limited pixel space the appearances produced by a given procedure.Unlike grids of thumbnails our previews present a continuous image of appearances, analog to a map.The main challenge is to ensure that most appearances are visible, are allocated a similar pixel area, and are ordered in a smooth manner throughout the preview.To reach this goal, we introduce a new layout algorithm accounting simultaneously for these criteria.After computing a layout of appearances, we rely on by‐example texture synthesis to produce the final preview.We demonstrate our approach on a database of production‐level procedural textures.

Multiple kernels noise for improved procedural texturing

Procedural texturing is a well known method to synthesize details onto virtual surfaces directly during rendering. But the creation of such textures is often a long and painstaking task. This paper introduces a new noise function, called multiple kernels noise. It is characterized by an arbitrary energy distribution in spectral domain. Multiple kernels noise is obtained by adaptively decomposing a user-defined power spectral density (PSD) into rectangular regions. These are then associated to kernel functions used to compute noise values by sparse convolution. We show how multiple kernels noise (1) increases the variety of noisy procedural textures that can be modeled and (2) helps creating structured procedural textures by automatic extraction of noise characteristics from user-supplied samples.

Realistic rendering of organ for surgery simulator

Realistic rendering of the organ surface appearance is necessary for high quality surgery simulator. It can greatly enhance visual realism and hence the overall quality of the VR simulators can be improved. This paper studied the realistic rendering methods of the organ surface, including organ texture synthesis, texture mapping and lighting computation for modeling mucous-covering of organ surfaces. Two different organ texture synthesis methods were presented: procedural texture generation based on Perlin noise, and applying an example synthesis based on an Ashikhmin algorithm. All kinds of organ textures were synthesized effectively. With regard to the visibility of seams and reducing the distortion, the created textures can be mapped to 3D mesh geometry by mesh parameterization. Blending between the different textures of patches reduced discontinuities. A kind of lighting computation method was described for modeling translucent mucous covering, in which incoming light is decomposed into its two components of surface reflection and sub-surface scattering that are then deal with respectively. Experimental results show that the proposed method is both feasible and effective.