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A procedural footprint enhancement of global topographic surface with multiple levels of detail

International Journal of Digital Earth 2020年第4期13卷 527-545页

作者： Lukáš Brůha Jan Kolář Faculty of Science Department of Applied Geoinformatics and CartographyCharles University in PraguePragueCzech Republic Grifinor Project CopenhagenDenmark

Virtual globes are technologies for visual navigation through a threedimensional,multi-resolution model of the entire *** representations used in virtual globes,however,lack geometric flexibility at high-resolution levels of the planet-wide terrain *** is a problem especially if boundaries between individual geospatial features and the terrain are important.A novel integration of individual polygonal boundaries with a specific multi-resolution representation of the planet-wide terrain is developed in this *** the preparation stage,the integration relies on an original simplification algorithm applied to the polygonal boundaries between geospatial features and the *** output is a multiple level-of-detail(LOD)geometry,which can be combined with a known multi-LOD representation of the terrain that uses run-time *** data representation is suitable for storage in existing database systems,avoids any data redundancy across LODs,and is even independent of the subdivision schema that partitions the planet’s surface for the sake of dealing with *** runtime,a novel reconstruction algorithm stitches geometric parts from different LODs together in a manner that augments the multi-LOD representation of the *** a certain proximity range from a given position,the method reconstructs a scene that preserves topological relations between the boundaries of geospatial features with the *** method also guarantees that certain nearest proximity to the given position consists of the best geometries that correspond to the original *** properties of the method close up the gap between a mere exploratory visualization of static,pre-generated models and the models supporting geospatial analysis,which is deemed crucial for applications in Geographic Information Systems,Building Information Modelling and other software industries.A prototype implementation and experiment results that prove this method are also prese

关键词： Feature-based topography multiple level-of-detail procedural modeling vector data organization geometry reconstruction

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procedural Facade Variations from a Single Layout

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ACM TRANSACTIONS ON GRAPHICS 2013年第1期32卷 1–13页

作者： Bao, Fan Schwarz, Michael Wonka, Peter Arizona State Univ Tempe AZ 85287 USA Cornell Univ Ithaca NY 14853 USA KAUST Taejon South Korea

We introduce a framework to generate many variations of a facade design that look similar to a given facade layout. Starting from an input image, the facade is hierarchically segmented and labeled with a collection of manual and automatic tools. The user can then model constraints that should be maintained in any variation of the input facade design. Subsequently, facade variations are generated for different facade sizes, where multiple variations can be produced for a certain size. Computing such new facade variations has many unique challenges, and we propose a new algorithm based on interleaving heuristic search and quadratic programming. In contrast to most previous work, we focus on the generation of new design variations and not on the automatic analysis of the input's structure. Adding a modeling step with the user in the loop ensures that our results routinely are of high quality.

关键词： Algorithms procedural modeling facade modeling design variations

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procedural Design of Exterior Lighting for Buildings with Complex Constraints

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ACM TRANSACTIONS ON GRAPHICS 2014年第5期33卷 1–16页

作者： Schwarz, Michael Wonka, Peter Cornell Univ Ithaca NY 14853 USA Arizona State Univ Tempe AZ 85287 USA King Abdullah Univ Sci & Technol Thuwal Saudi Arabia

We present a system for the lighting design of procedurally modeled buildings. The design is procedurally specified as part of the ordinary modeling workflow by defining goals for the illumination that should be attained and locations where luminaires may be installed to realize these goals. Additionally, constraints can be modeled that make the arrangement of the installed luminaires respect certain aesthetic and structural considerations. From this specification, the system automatically generates a lighting solution for any concrete model instance. The underlying, intricate joint optimization and constraint satisfaction problem is approached with a stochastic scheme that operates directly in the complex subspace where all constraints are observed. To navigate this subspace efficaciously, the actual lighting situation is taken into account. We demonstrate our system on multiple examples spanning a variety of architectural structures and lighting designs.

关键词： procedural modeling exterior lighting design

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Multi-Scale procedural Animations of Microtubule Dynamics Based on Measured Data

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IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS 2020年第1期26卷 622-632页

作者： Klein, Tobias Viola, Ivan Groeller, Eduard Mindek, Peter TU Wien Vienna Austria KAUST Thuwal Saudi Arabia VRVis Vienna Austria Nanographics GmbH Vienna Austria

Biologists often use computer graphics to visualize structures, which due to physical limitations are not possible to image with a microscope. One example for such structures are microtubules, which are present in every eukaryotic cell. They are part of the cytoskeleton maintaining the shape of the cell and playing a key role in the cell division. In this paper, we propose a scientifically-accurate multi-scale procedural model of microtubule dynamics as a novel application scenario for procedural animation, which can generate visualizations of their overall shape, molecular structure, as well as animations of the dynamic behaviour of their growth and disassembly. The model is spanning from tens of micrometers down to atomic resolution. All the aspects of the model are driven by scientific data. The advantage over a traditional, manual animation approach is that when the underlying data change, for instance due to new evidence, the model can be recreated immediately. The procedural animation concept is presented in its generic form, with several novel extensions, facilitating an easy translation to other domains with emergent multi-scale behavior.

关键词： procedural modeling molecular visualization animation microtubules

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Generalized selections for direct control in procedural buildings

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COMPUTERS & GRAPHICS-UK 2018年 72卷 106-121页

作者： Jesus, Diego Patow, Gustavo Coelho, Antonio Sousa, Antonio Augusto Univ Porto INESC TEC Porto Portugal Univ Porto DEI Fac Engn Porto Portugal Univ Girona ViRVIG Girona Spain

procedural modeling techniques reduce the effort of creating large virtual cities. However, current methodologies do not allow direct user control over the generated models. Associated with this problem, we face the additional problem related to intrinsic ambiguity existing in user selections. In this paper, we propose to address this problem by using a genetic algorithm to generalize user-provided point-and-click selections of building elements. From a few user-selected elements, the system infers new sets of elements that potentially correspond to the user's intention, including the ones manually selected. These sets are obtained by queries over the shape trees generated by the procedural rules, thus exploiting shape semantics, hierarchy and geometric properties. Our system also provides a complete selection-action paradigm that allows users to edit procedurally generated buildings without necessarily explicitly writing queries. The pairs of user selections and procedural operations (the actions) are stored in a tree-like structure, which is easily evaluated. Results show that the selection inference is capable of generating sets of shapes that closely match the user intention and queries are able to perform complex selections that would be difficult to achieve in other systems. User studies confirm this result. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： procedural modeling 3D model Semantics Genetic algorithms

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Edge-based procedural textures

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VISUAL COMPUTER 2021年第9-11期37卷 2595-2606页

作者： Kim, Hansoo Dischler, Jean-Michel Rushmeier, Holly Benes, Bedrich Purdue Univ W Lafayette IN 47907 USA Purdue Univ Technol W Lafayette IN 47907 USA Purdue Univ Comp Sci W Lafayette IN 47907 USA Univ Strasbourg Comp Sci Strasbourg France Yale Univ New Haven CT USA

We introduce an edge-based procedural texture (EBPT), a procedural model for semi-stochastic texture generation. EBPT quickly generates large textures from a small input image. EBPT focuses on edges as the visually salient features extracted from the input image and organizes into groups with clearly established spatial properties. EBPT allows the users to interactively or automatically design new textures by utilizing the edge groups. The output texture can be significantly larger than the input, and EBPT does not need multiple textures to mimic the input. EBPT-based texture synthesis consists of two major steps, input analysis and texture synthesis. The input analysis stage extracts edges, builds the edge groups, and stores procedural properties. The texture synthesis stage distributes edge groups with affine transformation. This step can be done interactively or automatically using the procedural model. Then, it generates the output using edge group-based seamless image cloning. We demonstrate our method on various semi-stochastic inputs. With just a few input parameters defining the final structure, our method can analyze the input size of 512 x 512 in 0.7 s and synthesize the output texture of 2048 x 2048 pixels in 0.5 s.

关键词： Texture synthesis procedural modeling Image analysis

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Integrating an urban green space typology into procedural 3D visualization for collaborative planning

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COMPUTERS ENVIRONMENT AND URBAN SYSTEMS 2014年 48卷 99-110页

作者： Neuenschwander, N. Hayek, U. Wissen Gret-Regamey, A. Swiss Fed Inst Technol Zurich Switzerland

Urban green spaces offer multiple ecosystem services (ES), which provide a variety of benefits to human well-being. Yet in urban planning they are not taken into account systematically. Recently new tools have been developed integrating ES into procedural modeling and visualization to raise stakeholder awareness for the explicit ES trade-offs that have to be made. These tools yet do not allow fast and comprehensive integration of ES provision in urban environments. In this paper we show how urban green space typologies can be linked to ES provision for facilitating collaboration between stakeholders of different backgrounds. Based on a generic typology green spaces were mapped and linked with information on potentially provided ES and their parameters. Further, pattern designs of the green space types were described with a form-based code. Both the map of green space types and the pattern designs were integrated into the parametric modeling and visualization chain of Esri CityEngine resulting in 3D visualizations of the green space patterns and correlating ES indicators. The green space typology allows for integrating different kinds of knowledge from both science and practice communities. The procedural model enables rapid interactive visualization of urban patterns and calculation of simple indicator values on the provision of ES. The simple approach for mapping green space types with low data requirements and the generic green space design patterns allow for transferability to other places and application to large areas. The developed approach is simple and fast yet comprehensive to communicate the vital importance of all green space types within the urban environment. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： Ecosystem services Urban planning procedural modeling 3D visualization Urban green space typology Generic pattern design

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Terrain Generation Using procedural Models Based on Hydrology

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ACM TRANSACTIONS ON GRAPHICS 2013年第4期32卷 1-13页

作者： Genevaux, Jean-David Galin, Eric Guerin, Eric Peytavie, Adrien Benes, Bedrich Univ Lyon LIRIS CNRS UMR5205 Lyon France Purdue Univ W Lafayette IN 47907 USA

We present a framework that allows quick and intuitive modeling of terrains using concepts inspired by hydrology. The terrain is generated from a simple initial sketch, and its generation is controlled by a few parameters. Our terrain representation is both analytic and continuous and can be rendered by using varying levels of detail. The terrain data are stored in a novel data structure: a construction tree whose internal nodes define a combination of operations, and whose leaves represent terrain features. The framework uses rivers as modeling elements, and it first creates a hierarchical drainage network that is represented as a geometric graph over a given input domain. The network is then analyzed to construct watersheds and to characterize the different types and trajectories of rivers. The terrain is finally generated by combining procedural terrain and river patches with blending and carving operators.

关键词： procedural modeling terrain generation hydrology

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Automatic Deep Inference of procedural Cities from Global-scale Spatial Data

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ACM TRANSACTIONS ON SPATIAL ALGORITHMS AND SYSTEMS 2021年第2期7卷 1–28页

作者： Zhang, Xiaowei Shehata, Aly Benes, Bedrich Aliaga, Daniel Purdue Univ 305 N Univ St W Lafayette IN 47907 USA

Recent advances in big spatial data acquisition and deep learning allow novel algorithms that were not possible several years ago. We introduce a novel inverse procedural modeling algorithm for urban areas that addresses the problem of spatial data quality and uncertainty. Our method is fully automatic and produces a 3D approximation of an urban area given satellite imagery and global-scale data, including road network, population, and elevation data. By analyzing the values and the distribution of urban data, e.g., parcels, buildings, population, and elevation, we construct a procedural approximation of a city at a large-scale. Our approach has three main components: (1) procedural model generation to create parcel and building geometries, (2) parcel area estimation that trains neural networks to provide initial parcel sizes for a segmented satellite image of a city block, and (3) an optional optimization that can use partial knowledge of overall average building footprint area and building counts to improve results. We demonstrate and evaluate our approach on cities around the globe with widely different structures and automatically yield procedural models with up to 91,000 buildings, and spanning up to 150 km(2). We obtain both a spatial arrangement of parcels and buildings similar to ground truth and a distribution of building sizes similar to ground truth, hence yielding a statistically similar synthetic urban space. We produce procedural models at multiple scales, and with less than 1% error in parcel and building areas in the best case as compared to ground truth and 5.8% error on average for tested cities.

关键词： procedural modeling uncertain spatial data deep learning urban modeling content creation satellite imagery 3D urban modeling

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Inverse Design of Urban procedural Models

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ACM TRANSACTIONS ON GRAPHICS 2012年第6期31卷 1-11页

作者： Vanegas, Carlos A. Garcia-Dorado, Ignacio Aliaga, Daniel G. Benes, Bedrich Waddell, Paul Purdue Univ W Lafayette IN 47907 USA Univ Calif Berkeley Berkeley CA USA

We propose a framework that enables adding intuitive high level control to an existing urban procedural model. In particular, we provide a mechanism to interactively edit urban models, a task which is important to stakeholders in gaming, urban planning, mapping, and navigation services. procedural modeling allows a quick creation of large complex 3D models, but controlling the output is a well-known open problem. Thus, while forward procedural modeling has thrived, in this paper we add to the arsenal an inverse modeling tool. Users, unaware of the rules of the underlying urban procedural model, can alternatively specify arbitrary target indicators to control the modeling process. The system itself will discover how to alter the parameters of the urban procedural model so as to produce the desired 3D output. We label this process inverse design.

关键词： interactive procedural modeling inverse procedural modeling urban models

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