3D Tiles Research Articles

Leveraging cloud compute and open source software to generate 3D models from drone photography

Abstract. Modern drone platforms provide the opportunity to capture large quantities of high quality, geotagged aerial imagery quickly and over large distances, at a relatively low cost. As organisations increasingly turn to digital twin technology to manage their operations, rich, photorealistic three dimensional (3D) models of their assets become increasingly important. This paper describes how cloud computing, and container based serverless compute in particular, can be used together with open source software to generate a 3D model, converted to 3D tiles for optimised transmission, from images of large outdoor assets captured by drone. This approach offers a flexible and cost effective way to processing drone imagery into 3D models whilst allowing you to maintain ownership and control of your data.

Data-driven visual model development and 3D visual analytics framework for underground mining

Data visualisation is broadly utilised to aid in presenting complex information, facilitating decision-making, and enhancing operational efficiency in the mining sector. However, due to the extensive utilisation of CAD files and the complexity and difficulty of converting 2D drawings into 3D models, it is challenging to realise (near) real-time 3D data visualisation in mining applications. The difficulties are including site drawing complexity, lack of standardisation, time-consuming cleaning, and imperative manual intervention. This paper addresses these challenges by focusing on an automatic, data-driven approach for 3D visual model development in mining, with an emphasis on lifetime support and sustainability. Therefore, we introduce standardised visual model data diagram and proposed conversion workflows to leverage digitised 2D drawings in automatic 3D visual model development. Moreover, to improve visualisation efficiency and facilitate visual analytics construction in mining, this paper also proposes a 3D tile index methodology for efficient visual model reconstruction and generic production data integration. To ensure lifetime support and sustainable development in visualisation, we propose two model expansion schemes: one based on dxf file-driven model development, and the other one is interaction-oriented 3D model design and development, which the two schemes share the same data exchange and conversion workflows. Furthermore, to facilitate data fusion among various datasets, we also provide insights into revealing spatial–temporal patterns among multimodality data by real-time visualisation. These advancements aim to propel the field of underground mining visualisation, offering significant insights into enhancing the efficiency and safety of mining operations.

Ray-Tracing modeling for urban photovoltaic energy planning and management

The traditional Radiative Transfer Modelling solutions for Solar Energy monitoring and forecasting often provide outputs for a single point location or an area location. However, for high resolution representation of areas these solutions suffer due to low simulation speeds. This approach makes it difficult for decision-makers to accurately estimate the solar potential of the administrative area and plan installations accordingly. In this direction, the study introduces three-dimensional Ray-Tracing based radiative modeling which is a high-speed area-based solution for solar energy monitoring. The three-dimensional ray-tracing was simulated by using advanced graphic creation platforms and cloud computing in conjunction with satellite data of the clouds, aerosols, building shadows effects and three-dimensional representations of the city using Cesium 3D tiles and Unreal Engine ®. The entire system was developed in a hybrid model to be exploited by urban planners for solar PV installations and by electricity distribution system operators for energy management and efficient incorporation of the produced energy into the regular and smart grids. This study implements and analyses this Ray-Tracing model for solar photovoltaic energy potential estimation at a rooftop level for the city of Athens, Greece. The total rooftop exploitable area in Athens was found to be close to 34 km2, which is able to massively host distributed PVs followed by almost 4.3 TWh of annually produced energy, whilst Penteli (a Municipality in Athens) possessed a potential of 96.8 GWh with an exploitable area of just 0.8 km2. This amount of energy, in a hypothetical full coverage scenario, is able to provide for 48.7% of Athens’s total energy requirement. Similar year-long simulations were conducted using the EU’s largest rooftop solar installation at Stavros Niarchos Foundation Cultural Center and randomly selected rooftops having solar installations in different municipalities in Athens. With these estimated solar potential values, the gross savings in natural gas consumption and hence the CO2 equivalent emissions can be computed. With the current estimated solar potential of Athens, the analyzed savings accounted of nearly 2.43 billion euros and 18 MT CO2 equivalent emissions. These computed annual savings are capable of covering installation costs for nearly 100,000 new solar installations. The end-product of this study is the development of a solar cadastre web tool which will support the decision-makers in the energy transition policies and the solar PV penetration into the urban environment and eventually drive the effort into renewable energy transition across the globe.

Construction of DNA Bilayer Tiles and Arrays Using Circular DNA Molecules as Scaffolds.

Using oligonucleotides to weave 2D tiles such as double crossovers (DX) and multi-arm junction (mAJ) tiles and arrays is well-known, but weaving 3D tiles is rare. Here, we report the construction of two new bilayer tiles in high yield using small circular 84mer oligonucleotides as scaffolds. Further, we designed five E-tiling approaches to construct porous nanotubes of microns long in medium yield via solution assembly and densely covered planar microscale arrays via surface-mediated assembly.

Research on the Visualization of Railway Signal Operation and Maintenance Based on BIM + GIS

To adapt to the “fine” and “extensive” management characteristics of railway signal equipment operation and maintenance, achieving real-time and interactive monitoring of signal equipment operation status, and developing an integrated approach to equipment operation and maintenance, this paper takes a comprehensive management perspective. To create a lightweight BIM model, the Garland folding algorithm is utilized to simplify the IFC file format. Building on this approach, the data are divided based on building component division standards to obtain separate files containing geometric information and semantic attributes. The geometric information files are converted to a 3D Tiles format, combining BIM semantic attributes with semantic attribute files through an intermediate format. Dynamic data management is achieved by setting the octree space index structure in combination with a view-frustum culling algorithm. Then, the 3D Tiles target file is imported into the Cesium platform, and Node.js is used to achieve three-dimensional visualization of railway signal operation and maintenance. The proposed method is verified using an inbound signal as an example to assess its feasibility. The results demonstrate the potential of the proposed method to achieve stable integration between BIM equipment full lifecycle maintenance and GIS geographical space display. Railway signal equipment is endowed with comprehensive one-click information query functions for equipment positioning and spatial analysis, improving the efficiency and scientific decision-making level of equipment operation and maintenance.

Semantic 3D City Model Data Visualization for Smar t City Digital Twin

Digital Twin has gotten much attention from the industry and academics worldwide. Thank the achievements in the 4.0 industry have facilitated many chances in other fields such as smart city, disaster recovery, etc. 3D Cities geospatial infrastructure is an increasingly widely used technique for storing, operating, analyzing, and managing digital data for smart cities. Based on those things, we discuss applying the Digital Twin technique to Smart Cities for simulation and management purposes. In this field, CityGML is an emerging concept, thanks to its strength in exchanging as well as representing the attributes of smart city data, also known as smart cities, also known as a 3D geospatial information data standard of OGC(Open Geospatial Consortium). We present a scenario for visualizing a smart village in Busan, South Korea, in 3D by using Cesium, the platform for 3D Geospatial. In this study, we propose a method for converting 3D city models from RVT/IFC to Cesium 3D Tiles format for streaming on the Cesium 3D globe.

Optimal Volumetric Video Streaming With Hybrid Saliency Based Tiling

Volumetric video enables a six-degree-of-freedom (6DoF) immersive viewing experience and has a wide range of applications in entertainment and education, among others. Most existing approaches to volumetric video streaming are extensions of VR video streaming solutions that do not take into account user behavior and the properties of the video during the tiling process, and the complexity of decoding is high. To this end, we study volumetric video streaming in this paper and address the research questions mentioned above. In particular, we first propose a hybrid visual saliency and hierarchical clustering empowered 3D tiling scheme that better matches the user's field of view (FoV). Then, we build a quality of experience (QoE) model considering the volumetric video features as the optimization objective. In addition to the usual encoded version, we introduce the reconstructed version (i.e., decoded version, which allows the user to skip the decoding process and thus reduces the decoding overhead) and propose a joint computational and communication resource allocation scheme to achieve a trade-off between communication and computational resources to maximize the QoE. We perform exhaustive simulations and build a prototype system to verify the performance of the proposed tiling and transmission scheme. The results show that the proposed tiling and transmission scheme performs significantly better than the comparison schemes.

QoE-Driven Adaptive Streaming for Point Clouds

With increasing popularity of virtual reality and augmented reality, application of point clouds is in critical demand as it enables users to freely navigate in an immersive scene with six degrees of freedom. However, point clouds usually comprise large amounts of data, and are thus difficult to stream in bandwidth-constrained networks. It is therefore important, yet challenging, to efficiently stream the resource-intensive point clouds, such that the user's quality of experience (QoE) is guaranteed on a high-level but with a low bandwidth consumption. To this end, we propose a QoE-driven adaptive streaming approach for the tile-based point cloud transmission, to maximize the user's QoE while reducing the transmission redundancy. By exploiting the perspective projection, we specifically model the QoE of a 3D tile as a function of the bitrate of its representation, user's view frustum and spatial position, occlusion between tiles, and the resolution of rendering device. Based on this QoE model, we then formulate the QoE-optimized rate adaptation problem as a multiple-choice knapsack problem, which allocates bitrates for different tiles under a given transmission capacity. It is equivalently converted to a submodular function maximization problem subject to knapsack constraints, and solved by a practical greedy-based algorithm with a theoretical worst-case performance guarantee. The proposed algorithm is able to achieve a near-optimal performance, but with a very low computational complexity. Experimental results further demonstrate superiority of the proposed rate adaptation algorithm over existing schemes, in terms of both user's visual quality and transmission efficiency.

The Rule of Thirds: Controlling Junction Chirality and Polarity in 3D DNA Tiles.

The successful self-assembly of tensegrity triangle DNA crystals heralded the ability to programmably construct macroscopic crystalline nanomaterials from rationally-designed, nanoscale components. This 3D DNA tile owes its "tensegrity" nature to its three rotationally stacked double helices locked together by the tensile winding of a center strand segmented into 7 base pair (bp) inter-junction regions, corresponding to two-thirds of a helical turn of DNA. All reported tensegrity triangles to date have employed turn inter-junction segments, yielding right-handed, antiparallel, "J1" junctions. Here a minimal DNA triangle motif consisting of 3-bp inter-junction segments, or one-third of a helical turn is reported. It is found that the minimal motif exhibits a reversed morphology with a left-handed tertiary structure mediated by a locally-parallel Holliday junction-the "L1" junction. This parallel junction yields a predicted helical groove matching pattern that breaks the pseudosymmetry between tile faces, and the junction morphology further suggests a folding mechanism. A Rule of Thirds by which supramolecular chirality can be programmed through inter-junction DNA segment length is identified. These results underscore the role that global topological forces play in determining local DNA architecture and ultimately point to an under-explored class of self-assembling, chiral nanomaterials for topological processes in biological systems.

COMPUTING ARBITRARILY LARGE MESHES WITH LEVEL-OF-DETAIL SUPPORT FOR CESIUM 3D TILES

Abstract. In this paper we present an approach to compute arbitrarily sized meshes of large scale environments. The meshes can be reconstructed from laser-scanned point clouds or existing high-resolution meshes. The algorithm automatically builds a level of detail hierarchy in the Cesium 3D Tiles format using an octree partition. The main contribution of this paper is a method that ensures that the generated meshes for each level-of-detail stage are computed in a consistent manner to minimize visual artifacts between different detail levels during rendering. Furthermore, both the reconstruction and simplification algorithm are designed to constrain the memory consumption, which enables to process even very large data sets on consumer-grade hardware. The export into the Cesium 3D Tiles format allows to render such large meshes efficiently in all web-based viewers that support this format. In our experiments we evaluate the method on different datasets and assess the visual quality during the rendering process and analyze the memory footprint as well as the runtime behaviour.

Highly Symmetric, Self-Assembling 3D DNA Crystals with Cubic and Trigonal Lattices.

The rational design of nanoscopic DNA tiles has yielded highly ordered crystalline matter in 2D and 3D. The most well-studied 3D tile is the DNA tensegrity triangle, which is known to self-assemble into macroscopic crystals. However, contemporary rational design parameters for 3D DNA crystals nearly universally invoke integer numbers of DNA helical turns and Watson-Crick (WC) base pairs. In this study, 24-bp edges are substituted into a previously 21-bp (two helical turns of DNA) tensegrity triangle motif to explore whether such unconventional motif can self-assemble into 3D crystals. The use of noncanonical base pairs in the sticky ends results in a cubic arrangement of tensegrity triangles with exceedingly high symmetry, assembling a lattice from winding helical axes and diamond-like tessellation patterns. Reverting this motif to sticky ends with Watson-Crick pairs results in a trigonal hexagonal arrangement, replicating this diamond arrangement in a hexagonal context. These results showcase that the authors can generate unexpected, highly complex, pathways for materials design by testing modifications to 3D tiles without prior knowledge of the ensuing symmetry. This study expands the rational design toolbox for DNA nanotechnology; and it further illustrates the existence of yet-unexplored arrangements of crystalline soft matter.

PY3DTILERS: AN OPEN SOURCE TOOLKIT FOR CREATING AND MANAGING 2D/3D GEOSPATIAL DATA

Abstract. In recent years, the production of 3D geospatial data using formats such as IFC, CityGML and GeoJSON, has increased. Visualizing this data on the web requires solving a variety of problems, such as the massive amount of 3D objects to be visualized at the same time and the creation of geometry suitable for a 3D viewer. Cesium and OGC introduced the 3D Tiles format in 2015 to solve these issues. They have created a specific format optimized for streaming and rendering 3D geospatial content, based on the glTF format developed by Khronos. The recency of the 3D Tiles format implies the need to experiment around this format and to test its interoperability with other geospatial and urban data formats. There is also the will to innovate on the organization of 3D objects in order to offer a better control on the visualization. Therefore, there is a need for an open source tool capable of converting 3D geospatial data into 3D Tiles to visualize them on the web, but also to test and develop new methods of spatial clustering and creating Levels of Detail (LoD) of urban objects. We propose Py3DTilers in this paper, an open source tool to convert and manipulate 3D Tiles from the most common 3D geospatial data models: CityGML, IFC, OBJ, and GeoJSON. With this tool, we ensure that the generated 3D Tiles respect the specification described by the OGC, in order to be used in various viewers. We provide a generic solution for spatially organizing objects and for creating LoDs, while allowing the community to customize these methods to go further in finding efficient solutions for visualizing geospatial objects on the web.

VIABILITY TESTING OF GAME ENGINE USAGE FOR VISUALIZATION OF 3D GEOSPATIAL DATA WITH OGC STANDARDS

Abstract. Urban digital twins have become an essential factor for cities and communities to visualize, simulate and analyze data. The conventional geospatial standards work great with online platforms such as CesiumJS or ArcGIS API for JavaScript. However, their usage in different platforms such as game engines has not been well established yet. Game engines provide an interesting application case because they offer a different approach to visualizing large city models and provide a high graphical fidelity.This paper aims to answer how the existing standards, such as the API standards GeoVolumes and SensorThings, as well as the 3D model standards 3D Tiles and Esri Indexed 3D Scene Layer (I3S), can interact with game engines. For this purpose, three use-cases were selected and have been used to build applications. These focus on using sensor data in AR and different city development scenarios in a digital environment.This study shows that different geospatial standard formats such as 3D Tiles, I3S, and GL Transmission Format (glTF) can be used in game engines, either directly or over a GeoVolumes Server. Their implementation makes it possible to use the advantages of game engines with real-world datasets.

Georeferencing 3D Tiles Generated from Photogrammetry-Derived Mesh Using Ground Control Points

In order to achieve efficient visualization of massive 3D photogrammetry models on the web-based virtual globe, original photogrammetry 3D models should be converted into 3D Tiles with accurate georeferencing information to render on the correct surface position. There are a few software tools and online platforms for generating 3D Tiles and various ways to generate 3D Tiles were reported, but none of them do not provide a way to georeference 3D Tiles with GCPs. This paper is intended to suggest an approach to georeference 3D Tiles with GCPs based on the Kabsch algorithm which is very similar to georeferencing raster data with GCPs in the traditional GIS. First, we mathematically describe how to apply the Kabsch algorithm for georeferencing 3D Tiles with GCPs. Following this description, we demonstrate our implementation allowing constructing GCPs and calculating the “transform” property of 3D Tiles. Finally, we tested the suggested method in Construkted Reality which is the platform to stream and visualize massive photogrammetry and point clouds datasets.

Interlocking assemblies: Applications and methods

Interlocking assemblies are assemblies where all the parts, except a key part, are immobilized relative to one another, preventing the whole assembly from falling apart under external forces. Starting from the key part, interlocking assemblies can be repeatedly disassembled and re-assembled, facilitating reuse of the parts. Due to advantages in structural stability and disassemblability, interlocking assemblies have been used in a variety of applications, including puzzles, 3D printing, furniture, and architecture. However, designing interlocking assemblies is a highly challenging task because of the global nature of the interlocking property. To address this challenge, a number of computational methods and tools have been developed in the last decade, mainly by the computer graphics community, for designing and fabricating personalized interlocking assemblies with various geometric forms. The design problem is typically formulated as a shape decomposition, joint planning, or 3D tiling problem, according to the user provided input. In this paper, we review these problem formulations, classify the state-of-the-art computational design methods, and propose possible directions for future research.

Implementation of BIM + WebGIS Based on Extended IFC and Batched 3D Tiles Data: An Application in RCC Gravity Dam for Republication of Design Change Model

The construction of hydropower project is a complex management process, whose management covers the entire construction site. Building information modeling (BIM) + Web Geographic Information System (WebGIS) is an effective means to solve the management of the construction site and main structures. Industry foundation classes (IFC) is commonly used in architecture, engineering and construction (AEC) industry as a standard for BIM data exchange. However, as the components of hydropower projects have not been included in IFC standards, IFC needs to be extended in application. At the same time, WebGIS pays more attention to display whole scene and ignores the processing of high-precision models. There will be deficiencies in network transmission and browser rendering in WebGIS environment of elaborate BIM model. Therefore, the batched three dimensions (3D) Tiles data format, which uses Web Graphics Library (WebGL) as the standard for 3D model rendering, has been widely considered in recent years. At present, in the field of BIM and GIS fusion, the conversion of extended IFC to 3D Tiles data is still blank, and none of the current BIM modeling software has the ability to export the components of hydropower projects. This paper proposes an extended IFC export method based on Autodesk Revit and a data exchange from extended IFC to batched 3D Tiles. Finally, the effectiveness of this method is verified by a design modification case of roller compacted concrete (RCC) gravity dam.

A Neural-Network Quality Control scheme for improved Quantitative Precipitation Estimation accuracy on the UK weather radar network

AbstractIn this work, we present a new Quantitative-Precipitation-Estimation (QPE) quality-control (QC) algorithm for the UK weather radar network. The real-time adaptive algorithm uses a neural network (NN) to select data from the lowest useable elevation scan to optimize the combined performance of two other radar data correction algorithms: ground clutter mitigation (using CLEAN-AP) and vertical profile of reflectivity (VPR) correction. The NN is trained using 3D tiles of observed uncontaminated weather signals that are systematically combined with ground-clutter signals collected under dry weather conditions. This approach provides a way to simulate radar signals with a wide range of clutter contamination conditions and with realistic spatial structures while providing the uncontaminated “truth” with respect to which the performance of the QC algorithm can be measured. An evaluation of QPE products obtained with the proposed QC algorithm demonstrates superior performance as compared to those obtained with the QC algorithm currently used in operations. Similar improvements are also illustrated using radar observations from two periods of prolonged precipitation, showing a better balance between overestimation errors from using clutter-contaminated low-elevation radar data and VPR-induced errors from using high-elevation radar data.

MosaicExplorerJ: Interactive stitching of terabyte-size tiled datasets from lightsheet microscopy

We introduce MosaicExplorerJ, an ImageJ macro to stitch 3D tiles from terabyte-size microscopy datasets organized on a regular 2D grid. As opposed to existing software, stitching does not require any prior information on the actual positions of the tiles, or conversion of raw TIFF images to a multi-resolution format for interactive exploration and fast processing. MosaicExplorerJ was specifically designed to process lightsheet microscopy datasets from optically cleared samples. It can handle multiple fluorescence channels, dual-sided lightsheet illumination and dual-sided camera detection.

MosaicExplorerJ: Interactive stitching of terabyte-size tiled datasets from lightsheet microscopy

We introduce MosaicExplorerJ, an ImageJ macro to stitch 3D tiles from terabyte-size microscopy datasets organized on a regular 2D grid. As opposed to existing software, stitching does not require any prior information on the actual positions of the tiles, or conversion of raw TIFF images to a multi-resolution format for interactive exploration and fast processing. MosaicExplorerJ was specifically designed to process lightsheet microscopy datasets from optically cleared samples. It can handle multiple fluorescence channels, dual-sided lightsheet illumination and dual-sided camera detection.

MosaicExplorerJ: Interactive stitching of terabyte-size tiled datasets from lightsheet microscopy.

We introduce MosaicExplorerJ, an ImageJ macro to stitch 3D tiles from terabyte-size microscopy datasets. As opposed to existing software, stitching does not require any prior information on the actual positions of the tiles, sample fiducials, or conversion of raw TIFF images, and the stitched images can be explored instantly. MosaicExplorerJ was specifically designed to process lightsheet microscopy datasets from optically cleared samples. It can handle multiple fluorescence channels, dual-side lightsheet illumination and dual-side camera detection.