Takuma Kawamura

Visualization of Large-scale CFD Simulation Results Using Distributed Particle-Based Volume Rendering

In this paper, we present a technique for visualizing a large-scale irregular volume dataset that is generated from an LES-based CFD simulation. Since our computational mesh was too large for a single computational node, it was divided into multiple regions; moreover, the resulting file was comprised of various irregular volume datasets. In order to cope with the multiple volume datasets, we extended our particle-based volume rendering (PBVR) technique so to fit the distributed computing environment. We applied our distributed PBVR technique to an LES-based CFD simulation, which explores dental fricative sound sources in order to confirm the effectiveness of the technique.

Remote visualization system based on particle based volume rendering

In this paper, we propose a novel remote visualization system based on particle-based volume rendering (PBVR),1 which enables interactive analyses of extreme scale volume data located on remote computing systems. The re- mote PBVR system consists of Server, which generates particles for rendering, and Client, which processes volume rendering, and the particle data size becomes significantly smaller than the original volume data. Depending on network bandwidth, the level of detail of images is flexibly controlled to attain high frame rates. Server is highly parallelized on various parallel platforms with hybrid programing model. The mapping process is accelerated by two orders of magnitudes compared with a single CPU. The structured and unstructured volume data with ~108 cells is processed within a few seconds. Compared with commodity Client/Server visualization tools, the total processing cost is dramatically reduced by using proposed system.

Algebraic design of multi-dimensional transfer function using transfer function synthesizer

In this paper, we propose a novel transfer function (TF) design interface for multi-variate volume rendering. To design higher dimensional TFs in an general and flexible manner, a transfer function synthesizer (TFS) is developed. On the TFS, multi-dimensional TFs are generated by algebraic synthesis of one-dimensional TFs, which are designed based on the conventional GUIs or algebraic expressions. The TFS enables not only multi-variate volume rendering, but also general visualization techniques, such as surface visualization and image composition, within the framework of volume rendering. The TFS is implemented on the remote visualization system PBVR, and applied to various multi-variate scalar volume data generated from nuclear applications.Graphical abstract

In-situ visual exploration of multivariate volume data based on particle based volume rendering

A novel in-situ online visualization framework is developed based on the Particle Based Volume Rendering (PBVR), which renders multivariate volume data using view-independent particle data. Our online approach enables visualization of particle data with interactive view exploration and changes of multi-dimensional transfer functions at runtime. The runtime visualization show excellent strong scaling up to thousands of cores, and its computational cost is small. These features enable flexible in-situ data exploration for monitoring extreme scale simulations. The utility of the proposed framework is demonstrated by applying it to simulations of molten debris relocation in reactor pressure vessels using the JUPITER code.

Multivariate volume rendering using transfer function synthesizer implemented in remote visualization system PBVR

In this paper, we propose a novel transfer function design technique for multivariate volume rendering. This technique generates a multidimensional transfer function by logical synthesis of variables and transfer functions. This technique enables analysts to extract correlation of variables and to combine multivariate surface and volume shapes. And this technique is implemented in Remote Visualization System PBVR optimized to several supercomputers. An experiment for the multi-phase fuel melting simulation result in the nuclear energy field shows the powerful ability of this technique enough by extracting complex behavior of molten materials.

Hands-on seminar of remote visualization system PBVR

This seminar serves as a practical guide to Particle-Based Volume Rendering (PBVR) and its client-server system, which is one of a promising technique for large-scale visualization. The remote visualization using commodity software takes a long time from a few hours to a few days because of the explosive increase of the original data or polygon size, however the remote PBVR system enables interactive visualization by using pixel-based particle data on the client-server system. The remote PBVR system is developed as cross-platform and run on various supercomputers such as K computer, or user PC. Flexible GUI is implemented for analytical visualization for multivariate data. The goal of this course is to learn principle of PBVR and integrated particle-based visualization by using open-source remote PBVR system (http://ccse.jaea.go.jp/ja/download/software_eng.html) through the lecture and its demonstration.

Abstract: Remote Visualization for Large-Scale Simulation Using Particle-Based Volume Rendering

With the recent development of supercomputers, it is required to efficiently visualize the results of extremely large-scale numerical simulations with a few hundreds to several tens of thousands of parallel processes. Conventional offline-processing visualization approaches are facing difficulties such as transferring large-scale data and reassembly of extensive amount of computational result files, which are inevitable for sort-first or sort-last visualization methods [1]. On the other hand interactive visualization on a supercomputer is still limited. We propose a remote visualization system which has three features. First, our visualization system can avoid the reassembly of the result files. This system can generate rendering primitives on the same number of parallel processes of the numerical simulation. Second, this system enables users to interactively manipulate camera position and time progress. Third, this system is appropriate to overview entire physical values of computational space (volume data) by volume rendering.

High-resolution visualization Svstem or barge-scale irregular Volumes on a Tiled Display Wall

A 1 1 0 タイルド表示装置を用いた 大規模非構造格子データの高解像度可視化 小山田耕ニ^ (京都大学),坂本尚久(京都大学),桑野浩(京都大学),河村拓馬(京都大学) High-resolution visualization Svstem or barge-scale irregular Volumes on a Tiled Display Wall Koii KOYAMADA, Naohisa Sakamoto, Hiroshi Kuwano, Takuma Kawamura ABSTRACT I n t h i s paper , we propose a sys tem t h a t v i sua l i zes a large-sca le i r r e g u l a r v o l u m e d a t a s e t on a la rge-sca le d i sp l ay w i t h t he P a r t i c l e B a s e d V o l u m e R e n d e r i n g ( P B V R ) t echn ique a n d t he Sca lab le A d a p t i v e G r a p h i c s E n v i r o n m e n t ( S A G E ) . M e d i c a l i m a g i n g devices such as a C o m p u t e d T o m o g r a p h y (CT) sys tem can eas i l y m o d e l h u m a n i n t e r n a l o rgans i n 3 D geomet r ies , a n d a c o m p u t a t i o n a l f l u i d d y n a m i c s sys tem can t h e n ca l cu la te flow f ie lds f r o m these geomet r ies . A co l l abo ra t i ve v i s u a l i z a t i o n sys tem u s i n g t he T i l e d D i s p l a y W a l l ( T D W ) sys tem uses t he s i m u l a t i o n r e s u l t . We a p p l i e d t h e p roposed s y s t e m to t he ca l cu l a t ed o r a l cav i t y f l ow f i e l d to eva lua te i t s e f fec t iveness. K e y w o r d s T i led display wal l , large-scale volume rendering