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Realistic Rendering of Smoke and Clouds
Kopidol, Jan ; Žák, Pavel (referee) ; Jošth, Radovan (advisor)
This work discourses about methods of rendering volumetric data such as clouds or smoke in computer graphics and implementation of this feature to existing application. The first part is summary of techniques and tricks used in computer graphics to display such objects in scene, their pros and cons and the most used techniques of displaying volumetric data. Next part is more closely focused to choosed technique of rendering volumetric data with consideration of light behavior inside the volume (also called participating media) and basic relationships used used in computation. In following part of work there is short list of applications - renderers used to realistic rendering of scene, which are suitable for implementation of selected volumetric data rendering algorithm. Selected application - Blender is describled more deeply including its inner structure, especially rendering engine. Last part of work is dedicated to design, implementation and integration of rendering algorithm itself.
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Rendering of Underwater Scenes
Smutný, Martin ; Vlnas, Michal (referee) ; Milet, Tomáš (advisor)
Cílem této práce je vykreslení podvodních scén a světelných efektů typických pro takové scény interaktivně ve vysoké kvalitě. Práce se konkrétně zaměřuje na fyzikálně založené vykreslování oceanických vod, které mají komplexní a vysoce proměnlivé optické vlastnosti. Vykreslování takových prostředí vyžaduje simulaci simulaci rozptylu světla uvnitř vodního objemu. Byly důsledně prozkoumány relevantní metody pracující v reálném čase. Byla navrhnuta jednoduchá oceanická scéna, které se skládá z procedurálně generovaného terénu, vodního povrchu a atmosferického modelu. Byl navrhnut fyzikálně založený bio-optický model vodního objemu. Rozptyl prvního řádu je aproximován, tím, že jsou vykreslovány fyzikálně založené povrchové a volumetrické kaustiky, vznikající lomem světla skrze vodní povrch. Vícenásobný rozptyl je aproximován na základě vlastností takových vod. Navržené techniky byly implementovány. Scénu je možné vykreslit z pohledu nad i pod povrchem vody. Techniky vykreslují efekty vodního objemu v přijatelné kvalitě a interaktivity bylo dosaženo na GPU nižší třídy.
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Rendering of Underwater Scenes
Smutný, Martin ; Vlnas, Michal (referee) ; Milet, Tomáš (advisor)
Tato práce se zabývá vykreslováním realistických podvodních scén pomocí technik v reálném čase. Práce se zaměřuje na vykreslování oceanických vod, které mají komplexní a vysoce proměnlivé optické vlastnosti. Vykreslování takových prostředí je náročnou oblastí v počítačové grafice, která zahrnuje simulaci rozptylu světla uvnitř vodního objemu. Jsou zkoumány metody počítačové grafiky pracující v reálném čase pro vykreslování a simulaci oceánů. Jsou navrhnuty techniky aproximující rozptyl první řádu a vícenásobný rozptyl pro vykreslení vodního objemu za pomocí krokování paprsku. Optické vlastnosti objemu jsou popsány pomocí fyzikálně založeného bio-optického modelu. Navíc, jsou vykresleny povrchové a volumetrické kaustiky odpovídající lomu světla skrze simulovaný vodních povrch pomocí Fourierovy transformace. Navržená technika pro vykreslování scén nebyla implementována v plné podobě. Byly implementovány pouze některé navržené techniky a s nimi byly provedeny experimenty zvlášť.
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Efficient visibility calculation for light transport simulation in participating media
Houška, Čestmír ; Křivánek, Jaroslav (advisor) ; Karlík, Ondřej (referee)
Title: Efficient visibility calculation for light transport simulation in participating media Author: Čestmír Houška Department / Institute: Department of Software and Computer Science Educa- tion Supervisor of the master thesis: doc. Ing. Jaroslav Křivánek, Ph.D. Abstract: This thesis investigates the use of acceleration methods for the testing of visibility in light transport calculation algorithms with the emphasis on conser- vativeness and low accelerated query overhead. Several published non-directional and directional distance field methods are presented with the description of their characteristic properties. Two of these methods are then implemented and thor- oughly tested in an existing rendering framework on a path tracing volumetric integrator as well as on an own implementation of a ray marching single scattering integrator. A method that further accelerates the original distance field methods by pre-caching results of some of the queries is also proposed, implemented and tested. Furthermore, several possible extensions to this method are outlined. Keywords: computer graphics, rendering, participating media, visibility
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Physically-based Cloud Rendering on GPU
Elek, Oskár ; Wilkie, Alexander (advisor) ; Křivánek, Jaroslav (referee)
The rendering of participating media is an interesting and important problem without a simple solution. Yet even among the wide variety of participating media the clouds stand out as an especially difficult case, because of their properties that make their simulation even harder. The work presented in this thesis attempts to provide a solution to this problem, and moreover, to make the proposed method to work in interactive rendering speeds. The main design criteria in designing this method were its physical plausibility and maximal utilization of specific cloud properties which would help to balance the complex nature of clouds. As a result the proposed method builds on the well known photon mapping algorithm, but modifies it in several ways to obtain interactive and temporarily coherent results. This is further helped by designing the method in such a way which allows its implementation on contemporary GPUs, taking advantage of their massively parallel sheer computational power. We implement a prototype of the method in an application that renders a single realistic cloud in interactive framerates, and discuss possible extensions of the proposed technique that would allow its use in various practical industrial applications.
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Procedurally Generated Volumetric Cloudscapes for Unity
Koblížek, Jan ; Kahoun, Martin (advisor) ; Rittig, Tobias (referee)
Title: Procedurally Generated Volumetric Cloudscapes for Unity Author: Jan Koblı́žek Department: Department of Software and Computer Science Education Supervisor: Mgr. Martin Kahoun, Department of Software and Computer Science Edu- cation Abstract: The traditional approach to cloud rendering in computer games is based on static sky- boxes or a set of static textures. Volumetric clouds used to be too computationally expensive, but with advances in GPU performance, they were successfully used in recent gaming titles. This thesis presents an implementation of real-time volumetric clouds for the Unity game engine. Clouds are described by multiple textures (both 3-dimensional and 2-dimensional) and rendered using a ray marching algorithm. The resulting implementation allows three types of low altitude clouds - cumulus, stra- tocumulus and stratus. The user can seamlessly transition between different coverages, times of the day, and animate clouds based of the speed and direction of the wind. Clouds support advanced lighting effects such as casting soft shadows and sun shafts. Keywords: clouds, volumetric raymarching, real-time rendering, Unity (game engine) 1
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Efficient GPU path tracing in solid volumetric media
Forti, Federico ; Elek, Oskár (advisor) ; Goel, Anisha (referee)
Realistic Image synthesis, usually, requires long computations and the simulation of the light interacting with a virtual scene. One of the most computationally intensive simulation in this area is the visualization of solid participating media. This media can describe many different types of object with the same physical parameters (e.g. marble, air, fire, skin, wax ...). Simulating the light interacting with it requires the computation of many independent photons interactions inside the medium. However, those interactions can be computed in parallel, using the power of modern Graphic Processor Unit, or GPU, computing. This work present an overview over different methodologies, that can affect the performance of this type of simulations on the GPU. Different existing ideas are analyzed, compared and modified with the scope of speeding up the computation respect to the classic CPU implementation. 1
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Real-Time Light Transport in Analytically Integrable Participating Media
Iser, Tomáš ; Elek, Oskár (advisor) ; Horáček, Jan (referee)
The focus of this thesis is the real-time rendering of participating media, such as fog. This is an important problem, because such media significantly influence the appearance of the rendered scene. It is also a challenging one, because its physically correct solution involves a costly simulation of a very large number of light-particle interactions, especially when considering multiple scattering. The existing real-time approaches are mostly based on empirical or single-scattering approximations, or only consider homogeneous media. This work briefly examines the existing solutions and then presents an improved method for real-time multi- ple scattering in quasi-heterogeneous media. We use analytically integrable den- sity functions and efficient MIP map filtering with several techniques to minimize the inherent visual artifacts. The solution has been implemented and evaluated in a combined CPU/GPU prototype application. The resulting highly-parallel method achieves good visual fidelity and has a stable computation time of only a few milliseconds per frame.
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Robust light transport simulation in participating media
Vévoda, Petr ; Křivánek, Jaroslav (advisor) ; Wilkie, Alexander (referee)
Light transport simulation is used in realistic image synthesis to create physically plausible images of virtual scenes. Important components of the scenes are participating media (e.g. air, water, skin etc.). Efficient computation of light transport in participating media robust to their large diversity is still an open problem. We implemented the UPBP algorithm recently developed by Křivánek et al. It addresses the problem by combining several complementary previous methods using multiple importance sampling, and excels at rendering scenes where the previous methods alone fail. The implementation is available online, we focused on its thorough description to facilitate and support further research in this field. Powered by TCPDF (www.tcpdf.org)
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Efficient visibility calculation for light transport simulation in participating media
Houška, Čestmír ; Křivánek, Jaroslav (advisor) ; Karlík, Ondřej (referee)
Title: Efficient visibility calculation for light transport simulation in participating media Author: Čestmír Houška Department / Institute: Department of Software and Computer Science Educa- tion Supervisor of the master thesis: doc. Ing. Jaroslav Křivánek, Ph.D. Abstract: This thesis investigates the use of acceleration methods for the testing of visibility in light transport calculation algorithms with the emphasis on conser- vativeness and low accelerated query overhead. Several published non-directional and directional distance field methods are presented with the description of their characteristic properties. Two of these methods are then implemented and thor- oughly tested in an existing rendering framework on a path tracing volumetric integrator as well as on an own implementation of a ray marching single scattering integrator. A method that further accelerates the original distance field methods by pre-caching results of some of the queries is also proposed, implemented and tested. Furthermore, several possible extensions to this method are outlined. Keywords: computer graphics, rendering, participating media, visibility
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