ISSN 2079-3537      

Scientific Visualization
Issue Year: 2013
Quarter: 4
Volume: 5
Number: 4
Pages: 88 - 117
Authors: D. Zhdanov (Russian Federation), S. Ershov (Russian Federation), N. Deryabin (Russian Federation)
  The paper is recommended by program committee of 23rd International Conference on Computer Graphics and Vision GraphiCon’2013.
Address: D. Zhdanov
Keldysh Institute for Applied Mathematics RAS, Moscow, Russian Federation
St. Petersburg National Research University ITMO, St. Petersburg, Russian Federation
Vavilov State Optical Institute, St. Petersburg, Russian Federation
S. Ershov
Keldysh Institute for Applied Mathematics RAS, Moscow, Russian Federation
N. Deryabin
Keldysh Institute for Applied Mathematics RAS, Moscow, Russian Federation
Abstract: The article is devoted to design of the object-oriented model of physically accurate visualization of the geometrically and optically complex scenes. The actuality of the object-oriented organization becomes clear if we design complex platforms for accurate light simulations and photorealistic rendering. In this case, all extra efforts spent to object-oriented design of the rendering and its database are overplayed because of time to extend the database are significantly reduced. For example, the addition of new type of geometrical element to the database or modification of the algorithm of photon map processing do not touch other components of the scene and renderer and require any addition modification in the software package.
The article considers basic principles of the object-oriented organization to design software for photorealistic visualization of complex scenes and discriminates two main components of the objet-oriented model: scene database and renderer. The article introduces conception of basic interfaces, which restrict all interactions between scene objects and between scene objects and renderer. For scene database, two levels of basic interfaces are proposed. The first level is a level of the end user. This level of interfaces is reduced to interfaces of entities, which are data structures with standard interfaces for self-visualization, user and program data modification and interaction with script. The second level is a level of the light simulations. For basic types of scene objects (geometry, camera, observer, light sources and optical properties), the minimal interface providing accurate and efficient ray tracing and calculation of direct and indirect luminances was designed. Moreover, for scene objects with a special behavior like scattering micro-geometry or special lenses, the conception optical elements is introduced. The interface of the optical elements joins interfaces of all other scene object types. A photorealistic scene visualization applies bi-directional stochastic ray tracing which provides physically correct light transfer from light sources through scene to camera. The ray tracer and renderer are designed on object-oriented principles too and all interactions of ray tracer and renderer with scene database is restricted with the basic interfaces.
Object-oriented model of the scene database and photorealistic visualization solution based on the bi-directional stochastic ray tracing were implemented in Lumicept software package. As an example, the article shows a result of computer visualization of LCD display of car dashboard under different conditions of interior and exterior illumination. The main specific of the visualization is physically accurate light simulation, which takes into account all details of the LCD construction, including scattering microstructures, polarization filters and TFT matrix.
The developed object-oriented model of photorealistic visualization is based on physically correct scene models including spectral and polarization light ray transformation incorporated to the basic interfaces of the proper object types. The conception of the optical element allows extending this object-oriented scene database with special objects, which interface cannot be expressed in the frames of standard scene object type. As a difference from most of computer solutions, the object-oriented conception was implemented for whole software package that significantly simplifies its extension with new scene and ray tracing models.
Language: Russian