Visualization of Three-Dimensional Geometric Models in a Stereoscopic System Rositsa Radoeva Assistant professor at St. Cyril and St. Methodius University of Veliko Tarnovo, Bulgaria

Introduction Stereopsis is the ability of humans to feel the depth of the scenes being viewed 2

3D objects in computer graphics  Polygon mesh;  Patch;  NURBS;  Bezier,etc. The information about the shape and colour of 3D models is stored in three-dimensional data files 3

The need for development of stereoscopic information system for visualization derives from the fact that in rendering three-dimensional space of the models and extraction of two-dimensional images there is a loss of depth in the image, which in certain situations is a disadvantage. 4

Problem definition A model of an appropriate architecture of stereoscopic information system and especially an approach for importation, presentation and visualization of three-dimensional geometric models (3DGM) could not be found in scientific publications. 5

Research tasks  Finding a suitable software solutions;  Development of an appropriate architecture and an algorithm for creation of such information system. 6

Benefits A system for stereoscopic visualization of 3D models will support the process of model observation and will provide the observer with more information about the presented model independently of the file format. Development of architecture of all- purpose cross-platform stereoscopic information system would be a useful model and applicable in many applied areas. 7

What we’ve done  The problem of stereoscopic visualization has been investigated;  An appropriate model for a stereoscopic virtual camera has been established;  The module of the system which provides stereoscopic visualization has been developed;  Methods for moving and rotating the cameras have been developed. 8

Model Loading Library To achieve the task that has been defined we need a library which is able to import as much as possible different file formats. After a search by the given criteria, the Open Asset Import Library (Assimp) has been selected. 9

Model Loading Library Assimp is able to import a lot of different model file formats by loading the entire model's data into Assimp's generalized data structures. After the library has loaded the model the application can retrieve all the data it needs from Assimp's data structures. Assimp sets itself apart from all the different file formats that exist because its data structure is independent from the imported types. 10

Model Loading Library 11

Developer's Image Library The DevIL library has been used for rendering the images that have been used as textures. It is a cross- platform image library which aims to provide a common API for different image file formats. The library has an OpenGL-like syntax. 12

Stereoscopic visualization using OpenGL  Getting confirmation that the graphics card supports stereoscopic display;  Loading the stereoscopic buffers;  Setting corresponding frustum parameters for two cameras and rendering the scene in two back buffers;  Swapping the front and back buffers. 13

Approach Briefly the process of importing a 3D model can be described as follows:  Loading an object into a Scene object;  Recursively retrieving the corresponding Mesh objects from each of the nodes;  Processing each Mesh object to retrieve the vertex data, indices and its material properties. The result is a collection of mesh data that should be contained in a single Model object. 14

Approach Classes and methods developed in the stereoscopic module are used to create the virtual camera. It has been realized parallel technique with asymmetric visual fields. 15

Approach The imported model is displayed twice as the offset between the two images that are determined by the positions of virtual stereo cameras. 16

Architecture 17

Demonstration 18

Demonstration 19

Graphical user interface Problem definition: A system for stereoscopic visualization requires an appropriate interface through which the user to perform different actions on the 3D model. It should be set a specific requirements in the process of designing GUI for the system but also the general interface requirements should be satisfied (e.g. is easy to use, prevents user disorientation). 20

Graphical user interface - overview  WIMP interfaces – users have become familiar with a particular set of WIMP UI components: windows, icons, menus and a mouse;  3D widgets - making the interface components first class objects in the same 3D environment 21

Development of graphical user interface for stereoscopic visualization system  Navigation;  Selection and Manipulation;  System Control. 22

Development of graphical user interface for stereoscopic visualization system Requirements:  possibility to open a file;  appropriate controls for performing rotation and translation along different axe in order to explore the 3D model;  controls for changing the properties of the 3D environment;  GUI should be a part of the graphic window. 23

Development of graphical user interface for stereoscopic visualization system Graphical User Interface library: GLUI is a GLUT-based C++ user interface library which provides controls such as buttons, checkboxes, radio buttons, spinners, and list boxes to OpenGL applications. 24

Development of graphical user interface for stereoscopic visualization system An approach 25

Development of graphical user interface for stereoscopic visualization system 26

Demonstration 27

Demonstration 28

Thank you for your attention! Rositsa Radoeva St. Cyril and St. Methodius University of Veliko Tarnovo, Bulgaria Mathematics and Informatics Faculty Computer Systems and Technologies Dpt.