• International Journal of Advanced Culture Technology
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• 제7권1호
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• pp.243-247
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• 2019

The most commonly used 3D modeling file formats are OBJ (Wavefront file format specification) and STL (STereoLithography). Although they have a common point of view in 3D on the screen, detailed functions are different according to purpose of development. OBJ is the most commonly used 3D file format and STL is mainly used as 3D file format for 3D printing. However, in the field of Scientific Visualization, precise analysis is required. There is a difference in accuracy depending on the type of 3D file format. OBJ and STL are not suitable for delicate surface description because they form meshes in the form of triangular polygons. And if you increase the number of triangle polygons, it will be smoother, but the file size also increases exponentially and causes excessive CPU usage. In contrast, VTK provides a variety of polygon structures, including triangular polygons as well as rectangular polygons and cube polygons. Thus, delicate surface depiction is possible. Delicate surface rendering is possible and file size is not large. This paper describes the concept and structure of VTK. We also compared the load times and file sizes between VTK, STL, and OBJ in the Chrome browser. In addition, the difference in surface rendering ability between VTK, STL, and OBJ is intuitively viewed based on the screen in which each 3D file format is implemented under the same conditions. This study is expected to be helpful for efficient 3D file format for precise implementation of Web - based Scientific Visualization.

• International journal of advanced smart convergence
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• 제8권1호
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• pp.65-74
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• 2019

3D file formats typically include OBJ (Wavefront file format), STL (STereoLithography), and FBX (Filmbox). Each format has limitations depending on its configuration and usage, and supported formats are different depending on the software application. glTF helps uniform integration of 3D file formats and allows for more efficient transmission of large 3D geometry files by organizing them in a binary format. This paper presents explanation on OBJ, FBX, and STL which are major examples of existing 3D file formats. It also explains the concept and characteristics of glTF and compares its performance with other 3D file formats on the web. The loading time and packets of each 3D file format are measured according to the web browser environment by means of Google Chrome, Firefox and Microsoft Edge. Experimental results show that glTF is the most efficient and that it exhibits the best performance. As to STL, relatively excessive traffic was observed. This study is expected to contribute to reducing rendering time on the web as 3D file formats are used.

• International Journal of Internet, Broadcasting and Communication
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• 제11권2호
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• pp.31-42
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• 2019

As smartphone H/W performance and mobile communication service have been enhanced, large-capacity 3D modeling files are available in smartphones. Common formats of 3D modeling files include STL (STereoLithography), OBJ (Wavefront file format specification), FBX (Filmbox), and glTF (open GL Transmission Format). Each format has different characteristics depending on the configuration and functions, and formats that are supported are varied depending on the applications. Large-size files are commonly used. The 4th generation mobile communication network secures loading of 3D modeling files and transmission of large-size geometric files in order to provide augmented reality services via smartphones. This paper explains the concepts and characteristics of major 3D file formats such as OBJ, FBX, and glTF. In addition, it compares their performance in a wired web with that in the 4th generation mobile communication network. The loading time and packet transmission in each 3D format are also measured by means of different mobile web browsers (Google Chrome and MS Edge). The experiment result shows that glTF demonstrated the most efficient performance while the loading time of OBJ was relatively excessive. Findings of this study can be utilized in selecting specific 3D file formats for rendering time reduction depending on the mobile web environments.

• 한국기계가공학회지
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• 제17권3호
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• pp.78-86
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• 2018

The 3D mesh model is used in various fields, such as virtual reality, shape-based searching, 3D simulation, reverse engineering, 3D printing, and laser scanning. There are various formats for the 3D mesh model, but STL and OBJ are the most typical. Since application systems support different 3D mesh formats, developing technology for converting 3D mesh models from one format into another is necessary to ensure data interoperability among systems. In this paper, we propose a method to convert a 3D mesh model in STL format into the OBJ format. We performed the basic design of the conversion system and developed a prototype, then verified the proposed method by experimentally converting an STL file into an OBJ file for test cases using this prototype.

• 한국CDE학회논문집
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• 제11권6호
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• pp.447-454
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• 2006

Although there are many needs to use 3D models in MEMS field, it is not easy to generate 3D models based on MEMS CAD. This is because MEMS CAD is based on 2D and their popular format-GDSII file format- has its own limits and problems. The differences between GDSII file format and 3D CAD system, such as (1) superposed modeling, (2) duplicated entity, (3) restricted of entity type, give rise to several problems in data exchange. These limits and problems in GDSII file format have prevented 3D CAD system from generating 3D models from the MEMS CAD. To remove these limits and solve problems, it is important to extract the silhouette of data in the MEMS CAD. The proposed method has two main processes to extract silhouette; one is to extract the pseudo-silhouette from the original 2D MEMS data and the other is to remove useless objects to complete the silhouette. The paper reports on the experience gained in data exchange between 2D MEMS data and 3D models by the proposed method and a case study is presented, which employs the proposed method using MEMS CAD IntelliMask and Solidworks.

• 한국콘텐츠학회논문지
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• 제7권8호
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• pp.134-141
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• 2007

3D 애니메이션 작업의 결과물을 출력하는데 있어서 동영상 파일로의 렌더링이 가능하지만 대부분의 프로덕션에서는 Image Sequence 렌더링 방식을 택하고 있다. 이러한 Image Sequence 렌더링 방식은 최종 영상물 제작을 위한 합성에 있어서 중요한 과정이다. 이러한 Image Sequence 렌더링 방식에는 다양한 Format의 이미지 형태들이 사용되는데 그 대표적인 것으로서 TGA format을 들 수가 있다. 하지만 TGA format 방식의 이미지가 이러한 과정에서 최적인가에 대한 의문점이 제기되어지고, 3D 프로그램마다 고유의 이미지 format을 가지고 있다는 점에서 이에 대한 연구가 필요하다. 본 연구에서는 Alias 사의 Maya를 중심으로 이러한 Image Sequence format에 대한 압축률, 선명도, 합성 시 필요한 Alpha Channel의 보존성, Z-Depth에 관한 Information에 관하여 연구하고자 한다. 이 연구의 결과는 3D 애니메이션을 Pipeline에 Image Sequence format에 대한 가이드 라인을 제공해주는데 목적이 있다.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2005년도 추계 종합학술대회 논문집
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• pp.131-136
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• 2005

3D 애니메이션 작업의 결과물을 출력하는데 있어서 동영상 파일로의 렌더링이 가능하지만 대부분의 프로덕션에서는 Image Sequence 렌더링 방식을 택하고 있다. 이러한 Image Sequence 렌더링 방식은 최종 영상물 제작을 위한 합성에 있어서 중요한 과정이다. 이러한 Image Sequence 렌더링 방식에는 다양한 Format의 이미지 형태들이 사용되는데 그 대표적인 것으로서 TGA format을 들 수가 있다. 하지만 TGA format 방식의 이미지가 이러한 과정에서 최적인가에 대한 의문점이 제기되어지고, 3D 프로그램마다 고유의 이미지 format을 가지고 있다는 점에서 이에 대한 연구가 필요하다. 본 연구에서는 Alias 사의 Maya를 중심으로 이러한 Image Sequence format에 대한 압축률, 선명도, 합성시 필요한 Alpha Channel 의 보존성, Z-Depth에 관한 Information에 관하여 연구하고자 한다. 이 연구의 결과는 3D 애니메이션을 Pipeline에 Image Sequence forma떼 대한 가이드라인을 제공해주는데 목적이 있다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.965-969
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• 1995

This paper deals with effective using the IGES file for flexible data exchange among the other CAD/CAM system. If a data exchange between STL file and the neutral IGES file in Stereolithography system is available, a product design becomes more flexible. THere can be many restrictions and difficulties intranslating these data. First, an STL file follows two rules, such as right-hand rule, and vertex-to-vertex rule, thus requires a structural verification. Second, translation should be performed with minmal errors. It becomes very important to translate IGES file of limited kinds of entities fot the purpose of geometric information into STL file with minor data manipulation. The developed system suggests a good approach of translating the sampled B-spline surface of IGES and shows a potential linkage between IGES and STL format file.

• 디지털융복합연구
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• 제14권1호
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• pp.189-194
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• 2016

최근 카메라, 캠코더 및 CCTV 등의 사용이 활발해지면서 영상 처리 기술의 수요가 급증하고 있다. 특히 키넥트 센서와 같은 깊이(Depth) 카메라를 사용한 3D 영상 기술에 대한 연구개발이 더욱더 활성화되고 있다. 키넥트 센서는 RGB, 골격(Skeleton) 및 깊이(Depth) 영상을 통해 인체의 3D 골격 구조를 실시간 프레임 단위로 획득할 수 있는 고성능 카메라이다. 본 논문에서는 키넥트 센서를 사용하여 인체의 3D 골격 구조를 모션 캡처하고 범용으로 사용되고 있는 모션 파일 포맷($^*.trc$ 및 $^*.bvh$)으로 선택하여 저장할 수 있는 시스템을 개발한다. 또한 본 시스템은 광학식 모션 캡처 파일 포맷($^*.trc$)을 자기식 모션 캡처 파일 포맷($^*.bvh$)으로 변환할 수 있도록 하는 기능을 가진다. 마지막으로 본 논문에서는 키넥트 센서를 사용하여 캡처한 모션 데이터가 제대로 캡처되어졌는지 모션 캡처 데이터 뷰어를 통하여 확인한다.

• 한국정밀공학회지
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• 제25권4호
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• pp.77-85
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• 2008

PDF is widely accepted as a standard document format and now it supports 3D contents as well. Within the engineering application areas, this new 3D feature may be used to support sharing of 3D documents and thus collaboration between engineering departments, suppliers and partners. In this paper, we describe a system that automatically generates formatted engineering documents including 3D data converted from 3D applications such as commercial 3D CAD viewer. The system consists of two major modules. One is U3D conversion module and the other is PDF conversion module. U3D conversion module extracts geometry, view data, assembly and disassembly information from 3D viewer and converts to U3D format, currently in IDTF text file format. PDF conversion module generates a PDF file and inserts U3D data, various annotation information, and scripts for custom generated operations such as assembly and disassembly in the PDF document.