Unlimited object instancing in real-time

In this paper, we propose a novel approach to efficient rendering of an unlimited number of 3D objects in real-time. We present a rendering pipeline that is based on a new computer graphics programming paradigm implementing a holistic approach to the virtual scene definition. Using Signed Distance Functions (SDF) for a virtual scene representation, we managed to control the content and complexity of the virtual scene with the use of mathematical equations. In order to solve the limited hardware problem, especially the limited capacity of the GPU memory, we propose a scene element repository which extends the idea of the data based amplification. The content of the repository strongly depends on a 3D object visualization method. One of the most important requirements of the developed pipeline is the possibility to render 3D objects created by artists. In order to achieve that, the object visualization method uses Sparse Voxel Octree (SVO) ray casting. The developed rendering pipeline is fully compatible with the available SVO algorithms. We show how to avoid occlusion errors which can occur in the SDF and SVO integration single-pass rendering pipeline. Finally, in order to control the content and complexity of the virtual scenes in an unlimited way, we propose a collection of global operators applicable to the virtual scene distance function. Developed Unlimited Object Instancing rendering pipeline can be easily integrated with traditional visualization methods, e.g. the triangle rasterization. The only hardware requirement for our approach is the support for compute shaders or any GPGPU API

Real-time voxel rendering algorithm based on screen space billboard voxel buffer with sparse lookup textures

In this paper, we present a novel approach to efficient real-time rendering of numerous high-resolution voxelized objects. We present a voxel rendering algorithm based on triangle rasterization pipeline with screen space rendering computational complexity. In order to limit the number of vertex shader invocations, voxel filtering algorithm with fixed size voxel data buffer was developed. Voxelized objects are represented by sparse voxel octree (SVO) structure. Using sparse texture available in modern graphics APIs, we create a 3D lookup table for voxel ids. Voxel filtering algorithm is based on 3D sparse texture ray marching approach. Screen Space Billboard Voxel Buffer is filled by voxels from visible voxels point cloud. Thanks to using 3D sparse textures, we are able to store high-resolution objects in VRAM memory. Moreover, sparse texture mipmaps can be used to control object level of detail (LOD). The geometry of a voxelized object is represented by a collection of points extracted from object SVO. Each point is defined by position, normal vector and texture coordinates. We also show how to take advantage of programmable geometry shaders in order to store voxel objects with extremely low memory requirements and to perform real-time visualization. Moreover, geometry shaders are used to generate billboard quads from the point cloud and to perform fast face culling. As a result, we obtained comparable or even better performance results in comparison to SVO ray tracing approach. The number of rendered voxels is limited to defined Screen Space Billboard Voxel Buffer resolution. Last but not least, thanks to graphics card adapter support, developed algorithm can be easily integrated with any graphics engine using triangle rasterization pipeline

Mit wrocławskiego Nadodrza. Gentryfikacja jako negatywna konsekwencja procesu rewitalizacji

Until recently, the northern Wrocław district of Nadodrze, has been perceived as one of the most neglected and dangerous areas of the city. Inhabited mainly by people with a low social status, by ethnic minorities or the unemployed, it seemed an unattractive place to live for representatives of higher echelons of the social ladder. Despite the poor opinion of Nadodrze, due to its historic character and central location, it has attracted avid interest of investors, developers and the city authorities. This triggered off restoration processes in the area which continues to this day. As a result, Nadodrze has changed its character. It has become an increasingly fashionable place to live and spend time. The effect of the restoration is also an inflow of representatives of the educated, more affluent middle class. Rental prices of accommodation and land have gone up; as a result, poorer groups of residents have been pushed out to other districts of the city. Among the consequences of restoration is gentrification, typically taking place in historic, post-industrial urban areas, which is also the case of Nadodrze. The gap between the former and the new inhabitants is widening. Tenants are being evicted and resettled from tenement houses. From a social point of view, this is a process of discrimination and marginalization of the former inhabitants of Nadodrze

Real-time visualization of dynamic unlimited objects instancing

In this paper, we propose a novel approach to an efficient rendering of an unlimited number of dynamic and unique 3D objects in real-time. We present an extension to the Holistic Unlimited Object Instancing (UOI) rendering pipeline and the holistic computer graphics paradigm. We called this extension Dynamic Unlimited Object Instancing rendering pipeline. Using Signed Distance Functions (SDF) for the virtual scene representation and the Holistic Scene Dynamics Function, we can control and render an unlimited number of dynamic 3D objects in real-time. In order to solve some issues of the original UOI rendering pipeline, we developed two extensions: first, a collection of holistic Dynamic operators, and, second, the Multipass Depth-Based Ray Marching rendering pipeline. The operators are used to apply affine transformations to an unlimited number of 3D objects and also to animate their materials and other attributes. In order to solve the problem of the uniform object distribution within the scene, we redefined the original definition of the scene SDF component. The virtual scene equation is divided into independent SDF components, which are rendered separately using the Multipass Depth-Based Ray Marching pipeline. Thanks to both extensions, the new version of the Holistic UOI rendering pipeline can handle 3D objects intersections what significantly enhances the realism of SDF scenes. The presented extensions to the UOI rendering pipeline are fully compatible with the Holistic UOI rendering pipeline, SDF and Sparse Voxel Octree (SVO) based algorithms. The only hardware requirement for our approach is the support for multipass rendering with compute shaders or any GPGPU API

Real-time rendering of continuous levels of detail for sparse voxel octrees

In this paper, we present a novel approach to real-time, continuous and symmetrical level of detail (LOD) management of a 3D object represented by a sparse voxel octree (SVO). We propose a new method for continuous and symmetrical transition between two detail levels. The method is based on a SVO representation extended by redundant, helper nodes which are used to achieve a proper interpolation of geometry and material data. We extend redundant nodes with a transition direction attribute. Additional memory requirements are minimized by storing indices in a direction vector lookup table in object space. The new method is applied for an accurate evaluation of the required LOD. It uses an image-based evaluation function, i.e. the standard level transition function based on camera distance is extended by the real-time calculation of the current LOD pixel fill rate. We extend typical level transition function based on distance with real-time calculation of the current LOD pixel fill rate. Two different image based methods of SVO node pixel fill rate calculations using compute shaders or GPU queries and parallel reduce are presented. The developed LOD management algorithm is applicable for a raytracing and a rasterizationbased rendering pipeline. The LOD transition algorithm allows to perform a dynamic and continues control of the SVO based objects which have not been available in other works. Moreover, the proposed fading algorithm based on the fade out direction and scaling allows for a LOD change without any graphical artifacts or loss of the virtual scene immersion

Unlimited object instancing in real-time

In this paper, we propose a novel approach to efficient rendering of an unlimited number of 3D objects in real-time. We present a rendering pipeline that is based on a new computer graphics programming paradigm implementing a holistic approach to the virtual scene definition. Using Signed Distance Functions (SDF) for a virtual scene representation, we managed to control the content and complexity of the virtual scene with the use of mathematical equations. In order to solve the limited hardware problem, especially the limited capacity of the GPU memory, we propose a scene element repository which extends the idea of the data based amplification. The content of the repository strongly depends on a 3D object visualization method. One of the most important requirements of the developed pipeline is the possibility to render 3D objects created by artists. In order to achieve that, the object visualization method uses Sparse Voxel Octree (SVO) ray casting. The developed rendering pipeline is fully compatible with the available SVO algorithms. We show how to avoid occlusion errors which can occur in the SDF and SVO integration single-pass rendering pipeline. Finally, in order to control the content and complexity of the virtual scenes in an unlimited way, we propose a collection of global operators applicable to the virtual scene distance function. Developed Unlimited Object Instancing rendering pipeline can be easily integrated with traditional visualization methods, e.g. the triangle rasterization. The only hardware requirement for our approach is the support for compute shaders or any GPGPU API

Real-time voxel rendering algorithm based on screen space billboard voxel buffer with sparse lookup textures

In this paper, we present a novel approach to efficient real-time rendering of numerous high-resolution voxelized objects. We present a voxel rendering algorithm based on triangle rasterization pipeline with screen space rendering computational complexity. In order to limit the number of vertex shader invocations, voxel filtering algorithm with fixed size voxel data buffer was developed. Voxelized objects are represented by sparse voxel octree (SVO) structure. Using sparse texture available in modern graphics APIs, we create a 3D lookup table for voxel ids. Voxel filtering algorithm is based on 3D sparse texture ray marching approach. Screen Space Billboard Voxel Buffer is filled by voxels from visible voxels point cloud. Thanks to using 3D sparse textures, we are able to store high-resolution objects in VRAM memory. Moreover, sparse texture mipmaps can be used to control object level of detail (LOD). The geometry of a voxelized object is represented by a collection of points extracted from object SVO. Each point is defined by position, normal vector and texture coordinates. We also show how to take advantage of programmable geometry shaders in order to store voxel objects with extremely low memory requirements and to perform real-time visualization. Moreover, geometry shaders are used to generate billboard quads from the point cloud and to perform fast face culling. As a result, we obtained comparable or even better performance results in comparison to SVO ray tracing approach. The number of rendered voxels is limited to defined Screen Space Billboard Voxel Buffer resolution. Last but not least, thanks to graphics card adapter support, developed algorithm can be easily integrated with any graphics engine using triangle rasterization pipeline

Perforacja przełyku – wyzwanie diagnostyczne i terapeutyczne. Jednoośrodkowa retrospektywna analiza przypadków z lat 2009–2015

Wstęp: Perforacja przełyku jest stanem bezpośrednio zagrażającym życiu pacjenta. Ten stan chorobowy charakteryzuje się złożoną etiologią oraz brakiem wytycznych co do standardów postępowania. Poniższa praca stanowi analizę przypadków leczonych w Klinice Chirurgii Klatki Piersiowej, Chirurgii Ogólnej i Onkologicznej oraz przegląd piśmiennictwa międzynarodowego dotyczącego tego zagadnienia. Cel badania: Celem badania była retrospektywna ocena i analiza postępowania u pacjentów z perforacją przełyku o zróżnicowanej etiologii, leczonych w Klinice Chirurgii Klatki Piersiowej, Chirurgii Ogólnej i Onkologicznej w latach 2009–2015. Z badania wyłączono grupę pacjentów, u których przyczyną perforacji była pooperacyjna nieszczelność w obrębie wykonanego zespolenia chirurgicznego. Materiał: Analizie poddano 16 przypadków perforacji przełyku, które były leczone w klinice w latach 2009–2016. Z analizy wykluczono przypadki nieszczelności chirurgicznych zespoleń u pacjentów poddanych planowym procedurom chirurgicznym zarówno z przyczyn nowotworowych, jak i nienowotworowych. Najczęstszą przyczyną perforacji były powikłania o charakterze jatrogennym (7 pacjentów; 44%), kolejną przyczyną był zespół Boerhaavego (5 pacjentów; 31,2%), perforacja w wyniku urazu tępego (2 pacjentów; 12,5%), perforacja w owrzodzeniu oraz perforacja w obrębie guza (po 1 pacjencie). Dziesięciu chorych leczono operacyjnie, 6 pacjentów poddano pierwotnemu protezowaniu przełyku – w tym w 2 przypadkach zastosowano drenaż śródpiersia i jamy opłucnej. W powyższej grupie chorych doszło do 9 zgonów (56,2%). Wnioski: Leczenie perforacji przełyku stanowi wyzwanie dla całego zespołu terapeutycznego. Począwszy od etapu diagnostyki, poprzez wybór metody leczenia pierwotnego, a następnie leczenie ewentualnych komplikacji. Badanie dotyczyło jednego ośrodka i pomimo szerokich ram czasowych retrospektywnie oceniono jedynie 16 przypadków. Pomimo niejednorodnej pod względem etiologii grupy, udało się uzyskać kilka istotności statystycznych niosących za sobą implikacje kliniczne. Większość rozpoznanych perforacji w czasie powyżej 48 godzin dotyczyła dolnego odcinka przełyku (częstsze ryzyko przeoczenia choroby w tym odcinku ze względu na niejasny obraz chorobowy i wyniki badań obrazowych). Rozpoznanie choroby i wdrożenie leczenia po 24 godzinach w naszym materiale wiązało się z wyższym odsetkiem zgonów

Oesophageal perforation – therapeutic and diagnostics challenge. Retrospective, single-center case report analysis (2009–2015)

Background: Esophageal perforation is a life-threatening condition of a complex etiology. No clear guidelines are available regarding the management of this condition. In this study, we review publications related to esophageal perforation, and analyze patients treated for this condition at our Department of Thoracic, General and Oncological Surgery. Objective: The objective of the study was to retrospectively assess and analyze management methods for esophageal perforations of different etiologies. All patients were treated in the Department of Thoracic, General and Oncological Surgery in years 2009-2015. Patients with perforations resulting from post-operational leaks within surgical anastomoses were excluded from the study. Material, methods, results: The analysis involved a total of 16 cases of esophageal ruptures. All cases were treated in years 2009-2015. Patients with perforations resulting from postoperative leaks within surgical anastomoses following elective surgeries for either oncological or non-oncological causes were excluded. The most common reason for esophageal rupture was iatrogenic injury (7 cases, 44%). Other causes included Boerhaave syndrome (5 cases, 31.2%), blunt trauma (2 cases, 12.5%), abscess perforation (1 case, 6.2%), and ulcer perforation (1 case, 6.2%). Ten patients underwent surgery, and the rest underwent esophageal prosthesis placement, of whom 2 cases required drainage of the mediastinum and pleural cavity. The mortality rate in the study group was 9/16 cases (56.2%). Conclusions: Esophageal perforation poses a significant interdisciplinary challenge regarding diagnostic workup, selection of treatment methods, and management of potential postoperative complications. This retrospective study was conducted in a single center. Although the analyzed period was long, we found only 16 cases. In spite of a variety of etiologies present, we found several statistically significant results of potential clinical value. 1. Most perforations that are not diagnosed within 48 hours affected the lower part of the esophagus and presented with unclear symptoms and imaging findings 2. Delaying diagnosis and treatment beyond 24 hours was associated with a higher mortality rate