MANOCHA D.: Gigawalk: Interactive Walkthrough of Complex Environments

"... We present a system for interactively producing exploded views of 3D architectural environments such as multi-story buildings. These exploded views allow viewers to simultaneously see the internal and external structures of such environments. To create an exploded view we analyze the geometry of the ..."

Abstract - Cited by 27 (5 self) - Add to MetaCart

We present a system for interactively producing exploded views of 3D architectural environments such as multi-story buildings. These exploded views allow viewers to simultaneously see the internal and external structures of such environments. To create an exploded view we analyze the geometry of the environment to locate individual stories. We then use clipping planes and multipass rendering to separately render each story of the environment in exploded form. Our system operates at the graphics driver level and therefore can be applied to existing OpenGL applications, such as first-person multiplayer video games, without modification. The resulting visualization allows users to understand the global structure of architectural environments and to observe the actions of dynamic characters and objects interacting within such environments.

Interactive Visibility Culling in Complex Environments using Occlusion-Switches

by Naga Govindaraju, Avneesh Sud, Sung-eui Yoon, Dinesh Manocha - Proc. of ACM Symposium on Interactive 3D Graphics , 2003

"... We present occlusion-switches for interactive visibility culling in complex 3D environments. An occlusionswitch consists of two GPUs (graphics processing units) and each GPU is used to either compute an occlusion representation or cull away primitives not visible from the current viewpoint. Moreover ..."

Abstract - Cited by 23 (6 self) - Add to MetaCart

We present occlusion-switches for interactive visibility culling in complex 3D environments. An occlusionswitch consists of two GPUs (graphics processing units) and each GPU is used to either compute an occlusion representation or cull away primitives not visible from the current viewpoint. Moreover, we switch the roles of each GPU between successive frames. The visible primitives are rendered in parallel on a third GPU. We utilize frame-to-frame coherence to lower the communication overhead between di#erent GPUs and improve the overall performance. The overall visibility culling algorithm is conservative up to image-space precision. This algorithm has been combined with levels-of-detail and implemented on three networked PCs, each consisting of a single GPU. We highlight its performance on complex environments composed of tens of millions of triangles. In practice, it is able to render these environments at interactive rates with little loss in image quality.

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Interactive shadow generation in complex environments

by Naga K. Govindaraju, Brandon Lloyd, Sung-eui Yoon, Avneesh Sud, Dinesh Manocha - ACM Trans. Graph , 2003

"... Figure 1: The left image shows a snapshot generated from the application of our hybrid shadow generation algorithm to the powerplant model (12.7M triangles). The middle image shows a different viewpoint generated using perspective shadow maps. Notice the aliasing artifacts. The right image highlight ..."

Abstract - Cited by 20 (8 self) - Add to MetaCart

Figure 1: The left image shows a snapshot generated from the application of our hybrid shadow generation algorithm to the powerplant model (12.7M triangles). The middle image shows a different viewpoint generated using perspective shadow maps. Notice the aliasing artifacts. The right image highlights the shadows generated by our interactive algorithm from the same viewpoint with sharper boundaries. Abstract: We present a new algorithm for interactive generation of hard-edged, umbral shadows in complex environments with a moving light source. Our algorithm is based on a hybrid approach that combines some of the efficiencies of image-precision techniques along with the image quality of object-precision methods. We present interactive algorithms based on levels-of-detail (LODs) and visibility culling to compute the potential shadow-casters and shadow-receivers. We further reduce their size based on a novel cross-visibility culling algorithm. Finally, we use a combination of shadow polygons and shadow maps to generate shadows. We also present techniques for LOD-selection that eliminate the artifacts in self-shadows. Our algorithm can generate sharp shadow edges and reduce aliasing. We have implemented the algorithm on a three PC system with NVIDIA GeForce-4 cards and applied it to three complex environments composed of millions of triangles. It can render the scene and generate shadows at 7 − 25 frames per second on these models.

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Simplifying Complex Environments using Incremental Textured Depth Meshes

by Andy Wilson, Dinesh Manocha - ACM TRANS. GRAPH , 2003

"... We present an incremental algorithm to compute image-based simplifications of a large environment. We use an optimization-based approach to generate samples based on scene visibility, and from each viewpoint create textured depth meshes (TDMs) using sampled range panoramas of the environment. The op ..."

Abstract - Cited by 19 (0 self) - Add to MetaCart

We present an incremental algorithm to compute image-based simplifications of a large environment. We use an optimization-based approach to generate samples based on scene visibility, and from each viewpoint create textured depth meshes (TDMs) using sampled range panoramas of the environment. The optimization function minimizes artifacts such as skins and cracks in the reconstruction. We also present an encoding scheme for multiple TDMs that exploits spatial coherence among different viewpoints. The resulting simplifications, incremental textured depth meshes (ITDMs), reduce preprocessing, storage, rendering costs and visible artifacts. Our algorithm has been applied to large, complex synthetic environments comprising millions of primitives. It is able to render them at 20 -- 40 frames a second on a PC with little loss in visual fidelity.

Fast and Simple Occlusion Culling using Hardware-Based Depth Queries

by K. Hillesland, B. Salomon, A. Lastra, D. Manocha , 2002

"... We present a conservative occlusion culling algorithm for large environments. As part of a preprocess, we decompose the scene using a spatial subdivision and render the primitives at runtime in a front-to-back order. Our algorithm uses hardware accelerated occlusion queries to test the visibility of ..."

Abstract - Cited by 16 (3 self) - Add to MetaCart

We present a conservative occlusion culling algorithm for large environments. As part of a preprocess, we decompose the scene using a spatial subdivision and render the primitives at runtime in a front-to-back order. Our algorithm uses hardware accelerated occlusion queries to test the visibility of more distant volumes of space in a progressive manner. The resulting algorithm is simple to implement and makes use of hardware features including the occlusion queries and vertex shaders for fast performance. We have implemented it on a PC with an NVidia GeForce3 card and are able to render a powerplant model composed of 12.5 million triangles at 10 20 frames a second. We are able to achieve a speedup of from four to ten times in frame rate with no loss in image quality.

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Interactive viewdependent rendering with conservative occlusion culling in complex environments

by Sung-eui Yoon, Brian Salomon, Dinesh Manocha - Proc. of IEEE Visualization , 2003

"... This paper presents a novel algorithm combining view-dependent rendering and conservative occlusion culling for interactive display of complex environments. A vertex hierarchy of the entire scene is decomposed into a cluster hierarchy through a novel clustering and partitioning algorithm. The cluste ..."

Abstract - Cited by 16 (3 self) - Add to MetaCart

This paper presents a novel algorithm combining view-dependent rendering and conservative occlusion culling for interactive display of complex environments. A vertex hierarchy of the entire scene is decomposed into a cluster hierarchy through a novel clustering and partitioning algorithm. The cluster hierarchy is then used for view-frustum and occlusion culling. Using hardware accelerated occlusion queries and frame-to-frame coherence, a potentially visible set of clusters is computed. An active vertex front and face list is computed from the visible clusters and rendered using vertex arrays. The integrated algorithm has been implemented on a Pentium IV PC with a NVIDIA GeForce 4 graphics card and applied in two complex environments composed of millions of triangles. The resulting system can render these environments at interactive rates with little loss in image quality and minimal popping artifacts.

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Fast and memory efficient view-dependent trimmed NURBS rendering

by Michael Guthe, Jan Meseth, Reinhard Klein - Pacific Graphics 2002 , 2002

"... The problem of rendering large trimmed NURBS models at interactive frame rates is of great interest for industry, since nearly all their models are designed on the basis of this surface type. Most existing approaches first transform the NURBS surfaces into polygonal representation and subsequently b ..."

Abstract - Cited by 12 (9 self) - Add to MetaCart

The problem of rendering large trimmed NURBS models at interactive frame rates is of great interest for industry, since nearly all their models are designed on the basis of this surface type. Most existing approaches first transform the NURBS surfaces into polygonal representation and subsequently build static levels of detail upon them, as current graphics hardware is optimized for rendering triangles.

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Surface reconstruction of large complex structures from mixed range data – The Erechtheion experience

by S. El-hakim, J. -a. Beraldin, M. Picard, L. Cournoyer - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol. 37, Part B5 (in the proceedings of this Congress , 2008

"... We present the procedure and technologies used to modelling of the Erechtheion at the Acropolis in Athens, a large complex structure with many challenges to data acquisition, processing, and visualisation. We used two scanners, one for medium range highresolution coverage (1-5 mm lateral data spacin ..."

Abstract - Cited by 10 (2 self) - Add to MetaCart

We present the procedure and technologies used to modelling of the Erechtheion at the Acropolis in Athens, a large complex structure with many challenges to data acquisition, processing, and visualisation. We used two scanners, one for medium range highresolution coverage (1-5 mm lateral data spacing) and one long-range scanner to capture some top sections occluded from the first scanner. We also used high-resolution digital images for image-based reconstruction using Photogrammetric and image matching techniques and for texture mapping. We focus in this paper on the geometric reconstruction from the range sensors. Several issues had to be addressed. Our system must be able to work with data obtained at different resolutions and accuracies and acquired from any viewpoint. The marble surfaces were of different age from one part to another due to decades of restoration. This resulted in different reflectance properties and apparent laser penetration that varied from area to area. Another problem resulted from the huge amount of data. The billions of generated 3D points by all sensors are currently beyond the processing capabilities of commercially available software or hardware. Reducing the data to a manageable size without losing important details had to be addressed. 1.

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