Millions Of Polygons Research Articles

Metaverse as Tech for Good: Current Progress and Emerging Opportunities

Metaverse is an upcoming transformative technology that will impact our future society with immersive experiences. The recent surge in the adoption of new technologies and innovations in connectivity, interaction technology, and artificial realities can fundamentally change the digital world. The Metaverse concept is the most recent trend to encapsulate and define the potential new digital landscape. However, with the introduction of 5G with high speed and low latency advancements in the hardware and software with the graphics power to display millions of polygons in 3D and blockchain technology, this concept is no longer fiction. This transition from today’s Internet to a spatially embodied Internet is, at its core, a transition from 2D to 3D interactions taking place in multiple virtual universes. In recent years, augmented virtual reality has created possibilities in the private and professional spheres. The new Virtual Reality (VR) headsets and Augmented Reality (AR) glasses can provide immersion in the physical sense. Technology must offer realistic experiences for users to turn this concept into reality. This paper focuses on the potential use cases and benefits of the Metaverse as a tech for good. The research paper outlines the potential areas where a positive impact could occur, highlights recent progress, and discusses the issues around trust, ethics, and cognitive load.

Saliency detection for large-scale mesh decimation

Highly complex and dense models of 3D objects have recently become indispensable in digital industries. Mesh decimation then plays a crucial role in the production pipeline to efficiently get visually convincing yet compact expressions of complex meshes. However, the current pipeline typically does not allow artists control the decimation process, just a simplification rate. Thus a preferred approach in production settings splits the process into a first pass of saliency detection highlighting areas of greater detail, and allowing artists to iterate until satisfied before simplifying the model. We propose a novel, efficient multi-scale method to compute mesh saliency at coarse and finer scales, based on fast mesh entropy of local surface measurements. Unlike previous approaches, we ensure a robust and straightforward calculation of mesh saliency even for densely tessellated models with millions of polygons. Moreover, we introduce a new adaptive subsampling and interpolation algorithm for saliency estimation. Our implementation achieves speedups of up to three orders of magnitude over prior approaches. Experimental results showcase its resilience to problem scenarios that efficiently scales up to process multi-million vertex meshes. Our evaluation with artists in the entertainment industry also demonstrates its applicability to real use-case scenarios.

Repair of Voids in Multi-Labeled Triangular Mesh

In this paper, we propose a novel mesh repairing method for repairing voids from several meshes to ensure a desired topological correctness. The input to our method is several closed and manifold meshes without labels. The basic idea of the method is to search for and repair voids based on a multi-labeled mesh data structure and the idea of graph theory. We propose the judgment rules of voids between the input meshes and the method of void repairing based on the specified model priorities. It consists of three steps: (a) converting the input meshes into a multi-labeled mesh; (b) searching for quasi-voids using the breadth-first searching algorithm and determining true voids via the judgment rules of voids; (c) repairing voids by modifying mesh labels. The method can repair the voids accurately and only few invalid triangular facets are removed. In general, the method can repair meshes with one hundred thousand facets in approximately one second on very modest hardware. Moreover, it can be easily extended to process large-scale polygon models with millions of polygons. The experimental results of several data sets show the reliability and performance of the void repairing method based on the multi-labeled triangular mesh.

Parametric directional coding for precomputed sound propagation

Convincing audio for games and virtual reality requires modeling directional propagation effects. The initial sound's arrival direction is particularly salient and derives from multiply-diffracted paths in complex scenes. When source and listener straddle occluders, the initial sound and multiply-scattered reverberation stream through gaps and portals, helping the listener navigate. Geometry near the source and/or listener reveals its presence through anisotropic reflections. We propose the first precomputed wave technique to capture such directional effects in general scenes comprising millions of polygons. These effects are formally represented with the 9D directional response function of 3D source and listener location, time, and direction at the listener, making memory use the major concern. We propose a novel parametric encoder that compresses this function within a budget of ~100MB for large scenes, while capturing many salient acoustic effects indoors and outdoors. The encoder is complemented with a lightweight signal processing algorithm whose filtering cost is largely insensitive to the number of sound sources, resulting in an immediately practical system.

SEGMENTATION OF 3D MODELS FOR CULTURAL HERITAGE STRUCTURAL ANALYSIS – SOME CRITICAL ISSUES

Abstract. Cultural Heritage documentation and preservation has become a fundamental concern in this historical period. 3D modelling offers a perfect aid to record ancient buildings and artefacts and can be used as a valid starting point for restoration, conservation and structural analysis, which can be performed by using Finite Element Methods (FEA). The models derived from reality-based techniques, made up of the exterior surfaces of the objects captured at high resolution, are - for this reason - made of millions of polygons. Such meshes are not directly usable in structural analysis packages and need to be properly pre-processed in order to be transformed in volumetric meshes suitable for FEA. In addition, dealing with ancient objects, a proper segmentation of 3D volumetric models is needed to analyse the behaviour of the structure with the most suitable level of detail for the different sections of the structure under analysis. Segmentation of 3D models is still an open issue, especially when dealing with ancient, complicated and geometrically complex objects that imply the presence of anomalies and gaps, due to environmental agents such as earthquakes, pollution, wind and rain, or human factors. The aims of this paper is to critically analyse some of the different methodologies and algorithms available to segment a 3D point cloud or a mesh, identifying difficulties and problems by showing examples on different structures.

Triton: Practical pre-computed sound propagation for games and virtual reality

Triton is a pre-computed wave-based acoustics system recently shipped in the game “Gears of War 4.” Games and VR present exciting new opportunities for virtual acoustics by providing the player with scene-dependent reverberation cues and conveying information about visually occluded areas. Several technical challenges must be met. Scenes containing millions of polygons are common, with mixed indoor-outdoor spaces like broken buildings, courtyards, caves, and rocks. A viable technique must handle this complex visual geometry without users' intervention. The emphasis is on ensuring the resulting auralization is perceptually convincing, varying smoothly on source and listener motion in such scenes. Highly occluded cases with salient paths undergoing multiple edge-diffraction and scattering are common. Computational requirements are quite stringent. A fraction of a single CPU core must be used for acoustic calculations for many tens of moving sources. We discuss how these challenges shape Triton’s design. Pre-computation is used to minimize runtime cost. Wave simulation provides complete automation for complex scene geometry. The produced fields contain billions of responses that take terabytes of memory. A key contribution is compact encoding of this data in less than hundred megabytes: objective room acoustic parameters are approached from a novel perspective to aid in spatial compression. The resulting parametric framework is fast and practical for current games and VR applications. Video demonstrations will be shown.

Tangible images of real life scenes

Haptic technologies allow for adding a new “touching” modality into virtual scenes. 3D reconstruction of a real life scene results, however, often in millions of polygons which cannot be simultaneously visualized and haptically rendered. In this paper, we propose a way of haptic interaction with real life scenes where multiple original images of the real scenes are augmented with reconstructed polygon meshes. We present our solution to the problems of haptic model alignment with the images and interactive haptic rendering of large polygon meshes with reconstruction artifacts. In particular, the presented collision detection algorithm is not restricted by any hypothesis and robust enough to support smooth interaction with millions of polygons. The feasibility and usability of the proposed solution is evaluated in a user study.

Forward Light Cuts: A Scalable Approach to Real-Time Global Illumination

We present Forward Light Cuts, a novel approach to real-time global illumination using forward rendering techniques. We focus on unshadowed diffuse interactions for the first indirect light bounce in the context of large models such as the complex scenes usually encountered in CAD application scenarios. Our approach efficiently generates and uses a multiscale radiance cache by exploiting the geometry-specific stages of the graphics pipeline, namely the tessellator unit and the geometry shader To do so, we assimilate virtual point lights to the scene's triangles and design a stochastic decimation process chained with a partitioning strategy that accounts for both close-by strong light reflections, and distant regions from which numerous virtual point lights collectively contribute strongly to the end pixel. Our probabilistic solution is supported by a mathematical analysis and a number of experiments covering a wide range of application scenarios. As a result, our algorithm requires no precomputation of any kind, is compatible with dynamic view points, lighting condition, geometry and materials, and scales to tens of millions of polygons on current graphics hardware.

Constrained Convex Space Partition for Ray Tracing in Architectural Environments

This paper explores constrained convex space partition CCSP as a new acceleration structure for ray tracing. A CCSP is a graph, representing a space partition made up of empty convex volumes. The scene geometry is located on the boundary of the convex volumes. Therefore, each empty volume is bounded with two kinds of faces: occlusive ones belonging to the scene geometry, and non-occlusive ones. Given a ray, ray casting is performed by traversing the CCSP one volume at a time, until it hits the scene geometry. In this paper, this idea is applied to architectural scenes. We show that CCSP allows to cast several hundreds of millions of rays per second, even if they are not spatially coherent. Experiments are performed for large furnished buildings made up of hundreds of millions of polygons and containing thousands of light sources.

Sparse GPU Voxelization of Yarn‐Level Cloth

AbstractMost popular methods in cloth rendering rely on volumetric data in order to model complex optical phenomena such as sub‐surface scattering. These approaches are able to produce very realistic illumination results, but their volumetric representations are costly to compute and render, forfeiting any interactive feedback. In this paper, we introduce a method based on the Graphics Processing Unit (GPU) for voxelization and visualization, suitable for both interactive and offline rendering. Recent features in the OpenGL model, like the ability to dynamically address arbitrary buffers and allocate bindless textures, are combined into our pipeline to interactively voxelize millions of polygons into a set of large three‐dimensional (3D) textures (>109 elements), generating a volume with sub‐voxel accuracy, which is suitable even for high‐density woven cloth such as linen.

A multiresolution representation for massive meshes

We present a new external memory multiresolution surface representation for massive polygonal meshes. Previous methods for building such data structures have relied on resampled surface data or employed memory intensive construction algorithms that do not scale well. Our proposed representation combines efficient access to sampled surface data with access to the original surface. The construction algorithm for the surface representation exhibits memory requirements that are insensitive to the size of the input mesh, allowing it to process meshes containing hundreds of millions of polygons. The multiresolution nature of the surface representation has allowed us to develop efficient algorithms for view-dependent rendering, approximate collision detection, and adaptive simplification of massive meshes. The empirical performance of these algorithms demonstrates that the underlying data structure is a powerful and flexible tool for operating on massive geometric data.

VLOD: High-Fidelity Walkthrough of Large Virtual Environments

We present visibility computation and data organization algorithms that enable high-fidelity walkthroughs of large 3D geometric data sets. A novel feature of our walkthrough system is that it performs work proportional only to the required detail in visible geometry at the rendering time. To accomplish this, we use a precomputation phase that efficiently generates per cell vLOD: the geometry visible from a view-region at the right level of detail. We encode changes between neighboring cells' vLODs, which are not required to be memory resident. At the rendering time, we incrementally construct the vLOD for the current view-cell and render it. We have a small CPU and memory requirement for rendering and are able to display models with tens of millions of polygons at interactive frame rates with less than one pixel screen-space deviation and accurate visibility.

Robust repair of polygonal models

We present a robust method for repairing arbitrary polygon models. The method is guaranteed to produce a closed surface that partitions the space into disjoint internal and external volumes. Given any model represented as a polygon soup, we construct an inside/outside volume using an octree grid, and reconstruct the surface by contouring. Our novel algorithm can efficiently process large models containing millions of polygons and is capable of reproducing sharp features in the original geometry.

Generation and adaptation of computational surface meshes from discrete anatomical data

AbstractFast and accurate scanning devices are nowadays widely used in many engineering and biomedical fields. The resulting discrete data is usually directly converted into polygonal surface meshes, using ‘brute‐force’ algorithms, often resulting in meshes that may contain several millions of polygons. Simplification is therefore required in order to make storage, computation and display possible if not efficient. In this paper, we present a general scheme for mesh simplification and optimization that allows to control the geometric approximation as well as the element shape and size quality (required for numerical simulations). Several examples ranging from academic to complex biomedical geometries (organs) are presented to illustrate the efficiency and the utility of the proposed approach. Copyright © 2004 John Wiley & Sons, Ltd.

Environmental design with huge landscape in real-time simulation system: Real-time simulation system applied to real project

This paper is the culmination of a period of studying and participating in certain real project on environmental design with real-time simulation system application. The focus of this paper is understanding that a generally real-time simulation system can render a complex scene that consisted a huge landscape model with millions of polygons and building models with thousands of details. It is also more than just a collection of unorganized techniques. This paper must deal with issues of scene elements management as a front end that efficiently provide the ability to process complex and moving objects in a physically realistic way. We establish a platform providing good support for the environmental designers.

Rendering complex scenes using spatial subdivision and textured LOD meshes

We present a hybrid rendering scheme that explores the locality of visibility at the cost of extra storage and prefetching, and makes a tradeoff between image quality and rendering efficiency by using textured level-of-detail (LOD) meshes. The space is first subdivided into cells. For each cell, inside objects are rendered as normal while outside objects are rendered as textured LOD meshes using projective texture mapping. The textured LOD meshes are object based and derived from the original meshes based on the captured depth images viewed at the centers of the cell and its adjacent cells. With such a textured LOD mesh, problems commonly found in image-based rendering, such as the hole problem due to occlusion among objects and the gap problems due to resolution mismatch, can be avoided. The size of holes due to self-occlusion is constrained to be within a user-specified tolerance. Several scenes with millions of polygons have been tested and higher than 200 FPS has been achieved with a little loss of image quality.

Time-critical multiresolution rendering of large complex models

Very large and geometrically complex scenes, exceeding millions of polygons and hundreds of objects, arise naturally in many areas of interactive computer graphics. Time-critical rendering of such scenes requires the ability to trade visual quality with speed. Previous work has shown that this can be done by representing individual scene components as multiresolution triangle meshes, and performing at each frame a convex constrained optimization to choose the mesh resolutions that maximize image quality while meeting timing constraints. In this paper we demonstrate that the nonlinear optimization problem with linear constraints associated to a large class of quality estimation heuristics is efficiently solved using an active-set strategy. By exploiting the problem structure, Lagrange multiplier estimates and equality-constrained problem solutions are computed in linear time. Results show that our algorithms and data structures provide low memory overhead, smooth level-of-detail control, and guarantee, within acceptable limits, a uniform, bounded frame rate even for widely changing viewing conditions. Implementation details are presented along with the results of tests for memory needs, algorithm timing, and efficacy.

The uc berkeley system for interactive visualization of large architectural models

Realistic-looking architectural models with furniture may consist of millions of polygons and require gigabytes of data-far than today's workstations can render at interactive frame rates or store ...

The UC Berkeley System for Interactive Visualization of Large Architectural Models

Realistic-looking architectural models with furniture may consist of millions of polygons and require gigabytes of data—far than today's workstations can render at interactive frame rates or store in physical memory. We have developed data structures and algorithms for identifying a small portion of a large model to load into memory and render during each frame of an interactive walkthrough. Our algorithms rely upon an efficient display database that represents a building model as a set of objects, each of which can be described at multiple levels of detail, and contains an index of spatial cells with precomputed cell-to-cell and cell-to-object visibility information. As the observer moves through the model interactively, a real-time visibility algorithm traces sightline beams through transparent cell boundaries to determine a small set of objects potentially visible to the observer. An optimization algorithm dynamically selects a level of detail and rendering algorithm with which to display each potentially visible object to meet a userspecified target frame time. Throughout, memory management algorithms predict observer motion and prefetch objects from disk that may become visible during imminent frames. This paper describes an interactive building walkthrough system that uses these data structures and algorithms to maintain interactive frame rates during visualization of very large models. So far, the implementation supports models whose major occluding surfaces are axis-aligned rectangles (e.g., typical buildings). This system is able to maintain over twenty frames per second with little noticeable detail elision during interactive walkthroughs of a building model containing over one million polygons.