Cesium for Omniverse v0.29.0

Cesium for Unity Samples v1.24.0

CesiumJS 1.143

Open Standards

At Cesium, we're passionate about working with the community to advance the intersection of computer graphics and 3D geospatial. SIGGRAPH has long been a place to connect on that work. We're excited to return this year and join the conversation in Los Angeles, California, USA, July 19-23. 

From Splats to Worlds: Advanced 3DGS Applications BOF 

Los Angeles Convention Center, Room 518 

Gaussian splatting has become one of the most exciting technologies for creating real-time, photorealistic 3D content. Join Daniel Zhong, fellow researchers, and industry experts for a discussion on bringing Gaussian splats to open standards, including the KHR_gaussian_splatting glTF extension and 3D Tiles. Presenters will also explore how hierarchical level of detail (HLOD) enables streaming geolocated, planet-scale splat scenes in real time and what's next for 4D Gaussian representations and other large-scale applications. 

Metaverse Standards Forum: 3D Assets: New Features, Tooling, and What Comes Next BOF 

Interoperable 3D assets are foundational to spatial computing, yet moving content across ecosystems remains harder than it should be. Henrik Edstrom will join industry leaders to discuss recent developments in glTF and OpenUSD, including emerging glTF 2.1 capabilities, interoperability between the two ecosystems, implementation status, and tooling. He will also highlight how 3D Tiles 2.0 builds on glTF 2.1 to enable scalable streaming of massive, semantically rich geospatial and digital twin content. 

ACM SIGGRAPH Cartographic Visualization Birds of a Feather (Carto BOF) 

Los Angeles Convention Center, Room 404 AB 

Hosted by our friend Theresa-Marie Rhyne, this session explores how computer graphics techniques can advance cartographic and geospatial visualization. Xuan Huang will present Cesium’s latest work on 3D-native vector visualization—streaming and rendering massive datasets at scale—developed as part of the 3D Tiles 2.0 open standard. The talk will highlight how the growing 3D geospatial ecosystem is delivering new capabilities to a broadening community of users.  

glTF 2.1 and Beyond: Building Interactive and Spatial 3D Experiences BOF 

Join Amanda Morgan and Sean Lilley for a look at how glTF continues to evolve for interactive and spatial 3D experiences. The session will cover the latest capabilities in glTF 2.1 and how they enable richer geospatial content, large-scale digital twins, and more immersive real-time applications. 

Cesium is proud to sponsor the Khronos Networking Reception. Wrap up the day by joining members of the Khronos community for an evening of demos, conversations, and networking. Stop by the Cesium table to meet the team, see our latest demonstrations (including a Mars rover experience), and connect with others building the future of open 3D. Please RSVP if you plan to join us. 

Don McCurdy will join Tam Belayneh from Esri to explore how glTF and 3D Tiles are enabling runtime-efficient streaming of geospatial content and digital twins. This session will cover a broad range of data types—including Gaussian splats, point clouds, vector data, volumetric data, and AEC/BIM content—and discuss how new glTF 2.1 scene capabilities support increasingly complex datasets at global scale. 

From Birds of a Feather sessions to standards discussions and community events, it's shaping up to be a busy week of learning, collaboration, and innovation. Whether you're interested in geospatial visualization and analysis, digital twins, open standards, or real-time 3D, we'd love to connect. 

If you'll be at SIGGRAPH 2026, stop by one of our sessions or say hello during the Khronos Networking Reception. See you in Los Angeles! 

One of the most frequent and long-standing requests from the community has been support for large-scale heterogenous vector data as part of 3D Tiles. We’re excited to share that we’re adding 3D-native vector points, lines, and polygons support to 3D Tiles 2.0. We’re looking for your feedback to help shape the specification and implementations.

Vector data scales quickly with geospatial datasets. Here, traffic volume is displayed on regional road network of 150,000 links (polylines) from OpenPaths transport model. Data courtesy of Atlanta Regional Council. Results do not correspond to any specific transportation planning scenario.

Vector data is widely used in architecture, engineering, construction, and operations, as seen in this 3D design model of a building with annotations, levels, and tags represented as vector data.

Before designing a solution, we conducted an extensive survey of the vector data ecosystem and of use cases, workflows, and widely adopted formats, including Mapbox Vector Tiles (MVT), MapLibre Tiles (MLT), and GeoJSON.

The 3D geospatial community’s use cases have focused on 3D vector data as a gap in current solutions. Use cases such as traditional city-scale road networks with centimeter precision on terrain, highly detailed models of transmission and telecom towers overlayed with vector information, AI-extracted global-scale points of interest at accurate elevations, and 3D-specific engineering tasks like building constructions with detailed design strings and annotations—all require real-time level-of-detail streaming and high-precision 3D rendering and analytics.

There are numerous applications for vector data as 3D Tiles. Here vector data is derived by iTwin Capture AI Analysis from mobile mapping LiDAR.

Green lines mark cracks detected on the Robert Street bridge, St. Paul, Minnesota. Only a 3D-native approach to vector data can capture cracks above and beneath the bridge as seen here. Data courtesy of Collins Engineers, Inc., which leveraged drone photogrammetry and automatic crack detection to operate safer onsite, avoid traffic interruptions, and accelerate and improve bridge inspection and maintenance.

Linework display in EARTHBRAIN Smart Construction Dashboard. These proposed changes to 3D Tiles will enable better streaming and sharing of vector datasets in large, complex engineering projects.

At the same time, we've heard from the community about a plethora of use cases that are sufficiently served by existing 2D and 2.5D tiling solutions, with GeoJSON and Mapbox Vector Tiles as most commonly used solutions. Users have shared their desire to use this content in conjunction with 3D Tiles, such as Google Photorealistic 3D Tiles or a user’s own high-resolution reality mesh.

As we compared the use cases to existing solutions, the current landscape is heavily 2D-focused: optimized for flat map tiles, with limited pathways to 3D, restricting both the perceptual clarity of spatial data and overall scalability. This is insufficient for the high-precision 3D use cases.

To address the need for fully-3D vector content and support existing vector data ecosystems, we are:

extending 3D Tiles to support vector data through the upcoming 3D Tiles 2.0 standard, built on glTF, and

adding runtime support for Mapbox Vector Tiles in CesiumJS and Cesium for Unreal to complement the GeoJSON solution already in place, allowing users to bring their existing vector tiles into Cesium’s open-source ecosystem.

Supporting vector tiling enables efficient streaming and high-performance rendering in a true 3D, Earth-coordinate environment, all while preserving semantic-based operations like metadata querying, styling, and analysis—capabilities essential to traditional vector data use cases. Together, these additions give users an on-ramp for their existing vector workflows and a foundation for next-generation 2D and 3D vector visualization, all within a single, unified ecosystem.

Visualization from prototype: Cracks on the Robert Street bridge that extend both on the road surface and to the side curb, where a traditional 2D vector data visualization will be insufficient. Data, courtesy of Collins Engineers, Inc., is untiled GeoJSON and rendered directly in CesiumJS.

3D Tiles enable smooth streaming of global scale datasets, and support for vector data will  enable powerful streaming capability for vector datasets, too. Here, 300K points assets detected by computer vision by Blyncsy are visualized in CesiumJS.

In designing our approach to tiling vector data, we focused on meeting real community needs and explored both traditional 2D GIS and emerging 3D workflows. We spoke to users across a breadth of industries about their needs. By observing their use cases, we summarized the following initial requirements for a scalable, 3D-native vector format. These needs have informed our design.

Support 3D coordinates with graceful handling of 2D and 2.5D

Support querying and styling of per-element properties

Support 3D coordinates not referenced to Earth, e.g., Mars, Moon

Support flexible tiling schemes, e.g., quadtrees, octrees, k-d-trees, and discrete global grid systems (DGGSs), for cases where tiling schemes based on the Web Mercator projection are not suitable, like polar regions or vertical structures such as buildings or dams

High-fidelity, real-time visualization experience:

Efficient runtime deserialization using runtime-ready binary formats and GPU-ready compression

Accurate display allowing centimeter to millimeter precision, which is often required for aligning vector and non-vector (e.g., scanned) sources

Proposed 3D Tiles 2.0 specification and glTF extensions

In the upcoming 3D Tiles 2.0 specification, vector data will be natively supported by leveraging the same spatial indexing, attribute encoding, and level-of-detail organization that powers 3D meshes and point clouds today. This means users can visualize, query, and work with all of their data together in a single, unified workflow, bringing vector features into the same integrated experience their applications already rely on for 3D content.

3D Tiles will support points, lines, and polygons encoded efficiently as glTF assets. The content can be optionally compressed using Meshopt and Gzip compression for efficient storage and streaming. The proposed specification consists of one new 3D Tiles extension and two proposed glTF extensions:

3DTILES_content_gltf_vector (3D Tiles extension): Identifies tile contents as “vector data,” and informs runtimes on how to interpret that data. Enables vector support in 3D Tiles 1.1, with an equivalent extension planned for 3D Tiles 2.0 soon.

KHR_mesh_primitive_restart (glTF extension): Enables more efficient encoding of LINE_STRIP and LINE_LOOP topology in glTF, used in line and polygon data.

EXT_mesh_polygon (glTF extension): Provides a backwards-compatible representation of polygons for glTF, preserving polygon topology while including runtime-ready triangulation data for high-performance rendering.

glTF extensions including EXT_mesh_features and EXT_structural_metadata will also be used for vector tiles content to encode Feature IDs, properties, and metadata.

Looking Ahead: Cesium's Vector Tiles Roadmap

A high-level overview of vector data workflow for Cesium.

Our work on 3D Tiles specifications is always backed by reference implementations proving the approach and performance and addressing the use cases. We have started implementations for tiling massive vector data and LOD-enabled high-fidelity rendering in CesiumJS and Cesium for Unreal.

The pipeline for vector content in Cesium will consist of three key parts:

An optimized tiling pipeline to create 3D Tiles from vector data, with GeoJSON as the initial input format. As with our existing pipelines, the vector tiling capability will be available both via Cesium ion and for self-hosted services. Additional formats such as GeoPackage, shapefiles, and more will be supported based on community feedback.

glTF for optimized vector tile encoding, streaming, and rendering.

Runtime vector support in CesiumJS, Cesium Native, and Cesium for Unreal, with additional runtimes like Cesium for Unity based on community feedback.

Aiming for a full end-to-end pipeline in the first phase, we have begun with support for GeoJSON as the initial input format. The support includes commercial tiling, hosting, and streaming services in Cesium ion, with runtime support in CesiumJS and Cesium for Unreal. We have also begun supporting Mapbox Vector Tiles in CesiumJS, which will reuse the same rendering pipelines as 3D Tiles, thus benefitting performance improvements.

In the coming months, we will extend styling support, support 3D Tiles and terrain clamping, add more source formats for all our runtimes, and continue performance and robustness improvements.

Visualization from prototype: A 3D design for a hypothetical highway in Coffs Harbour, NSW, Australia as vector tiles, tiled into 3 LODs and produced by Bentley. The geometry carries real elevation values — the road structures are positioned in true 3D space.

Vector data as 3D Tiles: highway design

Visualization from prototype: New York City building footprints represent the full perimeter outline of each building as viewed from directly above. Tiled with 13 LODs. Styling of the polygon as blue and dashed outlines is done at runtime.

Vector data as 3D Tiles: NYC Building footprints

These reference implementations are intended to seed your testing and feedback to align the specification and roadmap to address your use-cases.  

We look forward to collaborating with the community to finalize vector data support in 3D Tiles 2.0 and implementations in Cesium. We need your input to solidify the specification and test the implementation. Please share your use case and observations in the Cesium community forum. We’d love to hear about how you plan to build applications with vector tiles.  

Help Shape Vector Data Support in 3D Tiles

The Netherlands, perhaps more than any other country, appreciates how critical what lies below the surface is to what's built above. Much of the country sits below sea level, meaning groundwater is high, and centuries of silt and sand deposits from continental rivers mean the soil is soft. Consequently, understanding the makeup of the ground is of paramount importance for city planning.

Bedrock.engineer visualizes large geospatial subsurface datasets using 3D Tiles voxels. Here they use 3D Tiles voxels to visualize GeoTOP, a public geological model of the Netherlands by the Dutch Geological Survey. Courtesy Bedrock.engineer.

Visualizing national scale subsurface data with 3D Tiles voxels

GeoTOP demo by Bedrock.engineer

Unfortunately, subsurface data is challenging to share: the science is highly technical, and visualizations are often limited to PDFs, hand‑drawn cross sections, or specialized desktop software. That’s why Bedrock.engineer was founded. Bedrock.engineer works to make geotechnical data—boreholes, CPT tests, ground models, and analysis results—more accessible and easier to integrate into the tools engineers and stakeholders use. One of their interests is 3D visualization of subsurface models in the browser. Using the 3D Tiles 2.0 draft voxels extension in CesiumJS, they are streaming large subsurface datasets, demonstrating how open-format 3D Tiles enables geological voxel models to be explored in spatial context directly in the browser. Open source software and open data formats are central to how Bedrock.engineer works.

Bedrock.engineer visualizes subsurface data, like these boreholes in Hong Kong, together with above ground data in CesiumJS. Courtesy Bedrock.engineer.

Subsurface visualization with 3D Tiles voxels

Voxel representations, which can model continuous volumes and store material properties such as soil type, are ideal for subsurface datasets that hold continuous data like sediment layers. But visualizing very large voxel datasets in a geospatial context was not possible with open standards before 3D Tiles support.

Bedrock.engineer visualizes GeoTOP’s 50m deep subsurface data covering the entire Netherlands in CesiumJS using voxels. Courtesy Bedrock.engineer.

With the addition of voxel support in the draft 3D Tiles 2.0 specification, Bedrock.engineer can now combine voxel‑based subsurface models with 3D Tiles’ hierarchical streaming. Voxel renderings are currently a 3D Tiles extension and are part of the 3D Tiles 2.0 proposal, which was described at the 134th OGC Member Meeting in March. Bedrock.engineer has built their own Python tooling to convert gridded scientific formats, such as NetCDF, into 3D Tiles. 3D Tiles makes it possible to visualize dense, volumetric datasets covering an entire nation directly in the browser.

Bedrock.engineer brings GeoTOP data into CesiumJS using the 3D Tiles open standard, as in this dataset from Amsterdam. Courtesy Bedrock.engineer.

3D Tiles voxels make visualizing geoscience models possible, and bringing those 3D Tiles into CesiumJS makes it usable. What Bedrock.engineer appreciates most about CesiumJS is that visualizations are widely accessible to anyone with the link, allowing technical and nontechnical stakeholders to interact with the data directly.

"What 3D Tiles voxels change is accessibility. Subsurface models that used to require specialist desktop software can now be explored directly in the browser, in true 3D, in spatial context with the world above ground. And because it’s an open format, there’s no lock-in: anyone can build on it and combine it with their own data. That considerably lowers the barrier." 

– Jules Blom, Cofounder Bedrock.engineer

By bringing subsurface data into CesiumJS, Bedrock.engineer is also able to combine that data with other datasets, including terrain and buildings, for a more complete picture. For city planning, seeing what is below ground is only valuable if it’s shown in context with the natural and built environment above. Building on CesiumJS, Bedrock.engineer has implemented multivariable filtering, allowing users to see just the relevant data for any given application.

Fence diagrams make it easier to see layers of subsurface sediment. Courtesy Bedrock.engineer.

A prime example of Bedrock.engineer’s work is their CesiumJS visualization of GeoTOP, a public geological model of the Netherlands by the Dutch Geological Survey. By bringing GeoTOP into CesiumJS as 3D Tiles, Bedrock.engineer can embed the model in any browser-based application, combine it with other datasets in spatial context, and build custom tools on top of it, all using an open standard.

Every square meter of land in the Netherlands is designated for a particular use, such as agricultural, urban development, or green space. Municipalities are legally obliged to consider subsurface data whenever it is relevant to a public task. Courtesy Bedrock.engineer.

The GeoTOP model is well suited for governments seeking to better understand the geological features of their area at a regional scale. In the Netherlands, government bodies are legally required to consult BRO subsurface data, including models like GeoTOP, whenever it is relevant to a public task. Bedrock.engineer’s visualization makes it easier to understand and communicate what that data actually shows. When a local government can clearly see what’s below ground, they can make better decisions around spatial planning, groundwater management, land subsidence, and dike safety assessments.

Such visualization can also be useful to building developers in the early stages of a project. Knowing whether they’ll be dealing with peat or sand makes a significant difference when considering foundation type. Though GeoTOP is not a substitute for a full geotechnical investigation, but it gives a useful first indication before that work begins.

Semi-transparent voxel rendering of geophysical models reveals subsurface structures, creating an X-ray–like view of the underground. Data courtesy Emerald Geomodelling, image courtesy Bedrock.engineer.

Bedrock.engineer is working to add GeoTOP data to the LEIA viewer, a CesiumJS-based digital twin for the provincial government of Zeeland, Netherlands. Bringing GeoTOP into LEIA will allow policy makers to see subsurface data in spatial context with other government datasets. Bedrock.engineer has also brought a shallow subsurface model of the Antwerp urban region and harbor into CesiumJS, visualized as 3D Tiles voxels.

Voxel support is part of the draft 3D Tiles 2.0 specification, a key aspect of our commitment to open standards. If you’re working with volumetric data, explore the 3D Tiles OGC Community Standard, try it in CesiumJS, and share your feedback on GitHub. We’d love to see your implementation.

Bedrock.engineer Streams Subsurface Data at Nation Scale with 3D Tiles Voxels

Amanda: We’re thrilled to welcome Don McCurdy to the Platform team at Bentley. I know Don through his work with open standards: he formerly co-chaired the 3D Formats working group responsible for glTF and created popular open source tools like glTF Transform. As the senior director of open standards at Bentley, vice chair of the Khronos 3D Formats working group, and co-chair of the Metaverse Standards Forum 3D Asset Interoperability working group, I’m passionate about the openness that standards enable. With an eye to the future of standards development, I sat down with Don and with Sean Lilley, who is a lead engineer behind 3D Tiles and a driving force in Cesium’s development, to talk about their contributions to open standards and what they see ahead as developers.

Amanda: Don, you’ve been deeply involved with the development of glTF, the Khronos standard for models and scenes. How did you first get involved in open standards?

Don: I happened to be personally interested in building my own projects with WebGL around the time draft versions of glTF 2.0 were coming together. Loading 3D models into the scene correctly was a real challenge—existing loaders weren’t enough if the format itself wasn’t designed for runtime transmission or isn’t carefully documented in a technical specification.

The vision for glTF immediately felt right—runtime transmission, detailed specifications, and a scope that was opinionated and focused enough for complete implementation and specification to be possible.  I started contributing to a glTF loader in three.js and was introduced to Patrick Cozzi and others at the Khronos Group soon after that.

After that, finding more ways to get involved was easy: there are always more interesting technical challenges than people to solve them. I was also very fortunate to be working with a team that allowed me to spend a percentage of my time on self-directed work in open standards and open source.

Since then I’ve written the glTF Transform library, which is popular for optimizing existing 3D models, but at the same time it’s a very flexible framework for creating or modifying glTF models, or managing custom glTF extensions. I’ve also written three-ish glTF loaders now (too many?)  and a couple popular viewers like gltf.report/.

Amanda: Sean, you’ve been a key contributor to 3D Tiles since its inception. 3D Tiles is an OGC community standard for streaming massive 3D datasets, and is built on glTF. What drew you into the open standards space?

Sean: I first got involved in open standards when I joined Cesium in 2015. Previously, I was using COLLADA and OpenGL in a personal game engine project and was already a big fan of Khronos. One of the first projects I worked on at Cesium was obj2gltf, which started during a code sprint in the Poconos, and later gltf-pipeline.

This was also the year 3D Tiles was announced; I contributed to the specification, CesiumJS implementation, tiling pipelines, and was quite active on the Cesium Community Forum.

Amanda: Both 3D Tiles and glTF have revolutionized the way people visualize 3D data, but that’s just the beginning. I know we have some key work going on in 3D Formats right now with a new glTF version on the horizon and a new 3D Tiles coming right behind it. How do you see these standards evolving over time?

Don: glTF has been successful over the years, at least in part because of its unique focus on efficient, last-mile transmission to runtime. The line glTF needs to walk as it evolves, I think, is to keep that focus while understanding that the mission is a moving target, and that capabilities of runtimes and last-mile 3D data are also evolving.

Other open source or standards projects like OpenPBR, MaterialX, and USD are worth mentioning here. While they don’t necessarily share that transmission-to-runtime goal, they absolutely represent an evolution (for the better!) in 3D content creation, and these changes feed into workflows around glTF.

Importantly, glTF today provides the “building block” for extension into very different use cases – 3D Tiles and VRM especially. I hope that doesn’t change; it’s an important balance of scope.

Sean: At the same time, the community might benefit from glTF and 3D Tiles converging over time. In 3D Tiles 1.0 we had the Batched 3D Model and Instanced 3D Model formats that wrapped binary glTF. In 3D Tiles 1.1 we saw these capabilities move into glTF extensions that allowed 3D Tiles to reference glTF directly.

And now, in the other direction, there's an industry wide push towards using glTF for complex scenes; for example, the AEC industry using glTF for massive design models, and e-commerce using glTF for level of detail.

It seems to me that 3D Tiles and glTF are meeting somewhere in the middle, while staying true to efficient transmission.

Amanda: What community projects using glTF and 3D Tiles are you keeping an eye on?

Don: I worked with R&D at The New York Times a few years back, and they’ve done some really excellent work using both glTF and 3D Tiles in different projects, such as visualizing the progress of the fires in Maui in 2023. They’ve also written “field guides” sharing their processes and learnings for publishing 3D content in journalism.

Sean: Ever since the Google Maps Platform released their worldwide dataset as 3D Tiles, members of the larger community have been building all sorts of interesting applications with that data, like visualizing building projects in context or showing stadium locations in sports reels.

I'm really looking forward to Cesium Native getting WebAssembly support so that we can bring Cesium Native's 3D Tiles streaming engine to the browser.

I'm also actively following Garrett Johnson's 3D Tiles Renderer for Three.js.

Amanda: It’s clear both of you have contributed significantly to the tools and standards making 3D graphics easier than ever to share. What does it mean for Bentley to bring this kind of talent together?

Sean: It’s exciting. Don’s work has influenced how developers and artists optimize and publish 3D content. His tools like glTF Transform and gltf.report are widely used. Having him on board means we’re doubling down on our commitment to open standards and high-quality tooling.

Don: I’ve collaborated with the team before, including on 3D Tiles 1.1. Joining Bentley now feels like a natural next step: Bentley’s investment in open standards is a big reason I’m here. It’s rare to find a company that not only uses open formats but invests in helping define them.

Amanda: For readers interested in pushing the forefront of open standards, how would you recommend getting involved?

Sean: The Cesium community forum is very active and a great place to help other people building in 3D. And the 3D Tiles repo on GitHub is a great place to share ideas.

Don: There’s always need for people to pitch in. If you’re passionate about open standards, the Khronos Group is always looking for volunteers interested in supporting the future of graphics. And the Metaverse Standards Forum, as you know, is doing some really interesting interdisciplinary work.

Amanda: We’re deeply committed to building the tools for an open ecosystem. If you’d like to join us, check out our current openings.

Advancing 3D Tiles and glTF in an Open Ecosystem

From roads and bridges to campuses and cities, infrastructure design relies on precise geospatial context. With its 2025 release, MicroStation—Bentley Systems’ flagship computer aided design (CAD) software—introduced support for Open Geospatial Consortium (OGC) 3D Tiles using Cesium Native to efficiently deliver that context to professionals worldwide. This integration also makes MicroStation the first CAD software to support Google Photorealistic 3D Tiles.

MicroStation is a foundational software application for infrastructure design, central to thousands of landmark projects. It’s trusted by architects, engineers, designers, drafters, and BIM managers to design, manage, and efficiently deliver infrastructure projects. Professionals across transportation, energy, utilities, construction, government, and campus and facility management sectors rely on MicroStation to bring their vision to life.  

The software has played a central role in countless notable infrastructure projects worldwide. Examples include London’s Crossrail Elizabeth Line, New York’s Governor Mario M. Cuomo Bridge, and the Sydney Airport. It was also recently used by Italian engineering firm Italferr to create a highly detailed digital twin of St. Peter’s Basilica to preserve its architectural and cultural significance.

London, UK, rendered with Google Photorealistic 3D Tiles in MicroStation.

Integrating 3D Tiles enables efficient streaming and visualization of massive geospatial datasets providing highly accurate real-world context within MicroStation. With the latest MicroStation release, users can now bring Google Photorealistic 3D Tiles and engineering-grade reality data formatted as 3D Tiles via Bentley iTwin Reality Management directly into their designs.   

“Support for 3D Tiles in Bentley’s MicroStation is a major step forward for the open geospatial ecosystem. It brings the 3D Tiles open standard into the hands of infrastructure professionals worldwide and unlocks new use cases across industries,” said Patrick Cozzi, Bentley chief platform officer and Cesium founder. 

Photorealistic 3D Tiles are a 3D mesh textured with high-resolution imagery, available for 2,500 cities and 49 countries, bringing real-world data to infrastructure visualizations. By replacing manual workflows for modeling and detailing existing environments, infrastructure professionals can focus their time on the proposed designs. This shift has led to major time savings: Tasks that previously consumed over 1,000 hours for long linear projects can now be completed in as little as 200-300 hours. 

Google Photorealistic 3D Tiles of the 17th Street Causeway Bridge, Fort Lauderdale, Florida, USA, seen through multiple viewports viewed in MicroStation.

This integration also marks the first Bentley application to use Cesium Native—a collection of high-performance C++ libraries designed for 3D geospatial applications. Cesium Native includes 3D Tiles runtime streaming, lightweight glTF serialization and deserialization, high-precision geospatial math types and functions, and support for a wide range of geospatial standards.  

To support MicroStation specifically, new capabilities were added to Cesium Native, including multiple viewport support and orthographic camera functionality. These features are now also available in Cesium for Unreal and will be added to other Cesium Native integrations based on the community’s interest.  

Pairing 3D Tiles and Cesium Native with MicroStation illustrates our commitment to expanding and strengthening the open geospatial ecosystem, creating new opportunities for developers and empowering users to design, manage, and deliver better, more resilient infrastructure. 

Bring detail and efficiency to your infrastructure projects with 3D Tiles.

MicroStation Advances Infrastructure Design with 3D Tiles

With our work at the intersection of computer graphics and 3D geospatial, Cesium has a long history with SIGGRAPH. We’re excited to join again this year—the team will be in Vancouver, Canada, August 10-14. 

Accelerating AEC Workflows with 3D Geospatial Context in Runtime Engines 

Vancouver Convention Centre, West Building, Ballroom C 

Cory Barr will join Adam Liss, Philip Luhn, and David Willard of HNTB to discuss how HNTB uses Cesium to enhance AEC workflows and integrate 3D geospatial context. 

glTF: Innovations in 3D Content Delivery and Use

Vancouver Convention Centre, East Building, Room 15 

Get an in-depth look at how glTF is evolving to support richer, more realistic textures and new interactive applications, including gaming and metaverse use cases. Sean Lilley will deliver "Advancements in glTF for Geospatial," covering Gaussian splats, voxels, AEC rendering, and glX.

ACM SIGGRAPH Cartographic Visualization Birds of a Feather (Carto BOF)

Vancouver Convention Centre, East Building, Room 8 

This session is organized by our friend Theresa-Marie Rhyne and explores how viewpoints and techniques from the computer graphics community can be effectively applied to cartographic and spatial datasets. Jake Adelgren will discuss 3D Tiles. 

Metaverse Standards Forum Frontier Workshop: Town Hall: Gaussian Splats - Ready for Standardization 

Gaussian splats are a rapidly emerging method for the fast and efficient creation of photorealistic 3D visualizations. This Frontier Workshop will address the current technologies, formats, and use cases and investigate the potential for standardization to enable interoperability and sustainable growth. Jason Sobotka and Patrick Cozzi will participate. 

Metaverse Standards Forum State of 3D Asset Interoperability using USD and glTF BOF 

This session covers updates on alignment of PBR materials, physics extensions, roundtripping between glTF and USD, interactivity, animation, FBX, and new geometric representations. Amanda Morgan, Adam Morris, and Patrick Cozzi will participate. 

Hands-On Class: A No-Code Introduction to Creating Geospatial Worlds with 3D Tiles and Cesium 

Vancouver Convention Centre, West Building, Exhibit Hall B 

This class walks participants through how to create global-scale virtual worlds using real-world geospatial data that leverages Cesium and 3D Tiles on the web and in game engines. Cory Barr will lead this hands-on lab. 

glTF & 3D Commerce: Unlocking New Possibilities for Real-Time 3D 

Fairmont Waterfront Hotel, British Ballroom 

Sean Lilley will address glX and 3D Tiles. 

Fairmont Waterfront Hotel, Waterfront Ballroom Foyer (lobby level) 

Cesium is proud to be a sponsor of this event. Meet members and enjoy a cold drink and snacks after a long day of sessions. See live demos in action and make some new connections. Please RSVP if you plan to join us. 

We look forward to seeing you in Vancouver! 

Editor's note: Cesium is committed to open source, open standards, and rapid innovation. We power training, planning, operations, and analysis across the US Department of Defense and Intelligence Community. We're proud to have collaborated with NUWC Division Newport and NSWC Carderock Division on this article about the impact of OTAs. Read the PDF here.

In March 2025, Defense Secretary Pete Hegseth issued the memo “Directing Modern Software Acquisition to Maximize Lethality,” mandating the use of the Software Acquisition Pathway for all Department of Defense (DOD) software development procurements. This memo also instructs DOD components to prioritize Other Transaction Authority agreements (OTAs) and Commercial Solutions Openings (CSOs) as the preferred methods for acquiring software capabilities. 

OTAs were created in 1958 to give DOD flexibility to incorporate business practices that reflect commercial industry standards and best practices into how it awards contracts. DOD historically employed OTAs in conducting research and development; in 2016, the National Defense Authorization Act expanded the use of OTAs to include prototype and production. This expansion provided the warfare centers with another alternative to a Federal Acquisition Regulation (FAR)-based procurement contract. 

NAVSEA’s warfare centers have been doing business this way for years. 

In 2016, the Undersea Technology Innovation Consortium (UTIC) was stood up as a non-profit research organization comprised of small and large technology companies, academia, and nonprofits who are developing undersea technologies and addressing defense and security challenges.  

By 2018, UTIC, represented by management firm Advanced Technology International, and NUWC Newport Division signed a three-year OTA contract (renewable for up to 10 years) to explore Undersea Technology Innovation in a broad range of undersea and maritime prototyping activities. NUWC Newport Division’s contracting professionals began exploring how to use OTA to deliver prototypes to the submarine Fleet faster and soon released its first Call for Topics under the OTA—the first warfare center to pursue this option.

Their success led to collaboration with other warfare centers including the Naval Surface Warfare Center (NSWC) Carderock Division via Dave Sracic, Distinguished Software Engineer for Fleet Signatures Systems.  

Sracic needed a solution that would let him approve software development without micromanaging it. In 2019, Sracic awarded two agreements utilizing NUWC Newport Division’s UTIC OTA, one of which went to Analytical Graphics Inc., whose subcontractor was Cesium.  

Cesium specializes in 3D geospatial technology, particularly for visualization and analysis. The company is considered a “non-traditional” government partner, which was a major aspect of the success of the collaboration. 

As part of the OTA prototype agreement, Cesium provided a platform for building 3D geospatial applications, including CesiumJS, an open-source library for 3D visualization in web browsers designed for robust interoperability and scaling for massive datasets. Cesium works to advance the geospatial ecosystem and open source, open standards, data sharing, and interoperability.  

In May 2024, NSWC Carderock awarded $2.2 million to Cesium through the OTA.  

Stills from Cesium’s bathymetry data set.

“UTIC had already proven to be effective for my team and our small initial toe-in-the-water approach had been highly successful. Given the choice between working with NUWC Newport to put together a new Request for Prototyping versus pursuing a traditional FAR-based path, it wasn’t much of a choice at all—I’ll take six weeks over 18 months any day,” said Sracic. 

Trent Tinker, director of Cesium’s federal business development, said, “From Cesium’s perspective, the OTA streamlined administrative processes and allowed for a direct line of communication with Navy customers. The OTA got us a step closer to the end users, and ensuring their data supports better, faster decisions is something that we’re really excited about.” 

According to Sracic, “Open source software is a building block of nearly every DOD system, and at some level, virtually all of the world’s most complex software systems. Our key challenge in building Navy combat systems is in using open-source software without finding ourselves trapped when it evolves faster than we do. Our thought was we’re using this open source CesiumJS and it does 80 percent of what we want, so let’s pay the experts who built it to make it do more.” 

As Sracic explained, “We got those changes back into CesiumJS, upstream, open source version, which means we do not have to keep a Navy fork of that software. The open source community maintains those specific changes. We care deeply about those features and use them heavily. Now that they’re part of the master branch, with test cases, we have reasonable confidence they won’t die, and we don’t pay some kind of sustainment fee. This is what the DOD policy aspires to—the government contributing back to open source.” 

“The OTA also enables Cesium to work with warfare centers on the open source position of their challenges,” said Tinker. “While some of the development stays with the government, other roadmap-aligned services go to the open source baseline and benefit everyone.” 

“Public-private partnerships between the Navy and UTIC members enable the Navy to create new paths to acquire and improve technological capabilities aboard its fleet, focusing on critical missions rather than the building blocks of visualization. Dave Sracic was proactive and flexible, and our terms were Firm Fixed Price, pairing our risk tolerance and desire to do meaningful work as a technology growth company,” said Patrick Cozzi, Cesium founder and Bentley Systems chief platform officer. 

“This is quantifiable value and return on investment, and sufficient to justify follow-on efforts to integrate capability into a combat system, which is a win for Navy in that it’s already risk-reduced and well understood,” explained Sracic. “And it’s a win for industry, which can do that work through non-competitive follow-on to the OTA.”

Our third installment highlights two more tracks at the 2025 Cesium Developer Conference: community-contributed aerospace and defense topics and sessions on Cesium, iTwin, OGC 3D Tiles, and other open technologies compiled by the teams at Cesium and Bentley Systems who work on them.

With Cesium’s roots in aerospace and commitment to interoperability and rapid innovation for tackling the hardest problems in 3D geospatial, we were excited to receive a group of full and lightning talk submissions focused on space, the Moon, flight systems, and mission-critical visualization and analysis.

To provide the community with a closer look into the advancements happening with Cesium and 3D Tiles, we decided to group a set of talks from the Platform team in Bentley Systems. The Platform team comprises development teams from Cesium, iTwin, and iTwin Capture, bringing together global geospatial, cloud-based-BIM (building information modeling), and reality capture.

Register for the Cesium Developer Conference

Calculating access to communications satellites in DigitalArsenal's OrbPro. Courtesy DigitalArsenal.

In today’s complex geopolitical environment, we’re seeing expanded interest in access to open geospatial technologies. Recent investments in the space industry have created satellite constellations with thousands of new spacecraft in just the last few years, and we’re hearing from developers who want to implement full global geospatial 3D experiences for training, planning, operations, and analysis.

These trends are reflected in the talk submissions we grouped in the Aerospace and Defense track, including:

A presentation by Maxar on 3D Tiles and One World Terrain

A photogrammetry sandbox built with Cesium for Unreal by the French Air Force

A flight status indication system from Takram

Military planning using agentic AI from our former colleague Brady Moore

Astronaut training on the Moon with Buendea

The Aerospace and Defense sessions are in a track the morning of June 24, and a series of seven lightning talks will be featured during the afternoon of the 24th on the main stage.

Maxar Precision3D Surface Model of Kabul International Airport. Courtesy Maxar Technologies.

We want the community to take center stage, and we want to feature enough sessions that developers can get a taste of what is happening now that Cesium is part of Bentley Systems.

The track focusing on Cesium, iTwin, and 3D Tiles will feature sessions on topics such as:

Bringing AI analytical tools for reality capture data into Cesium ion

Working with BIM data and the Design Tiler

How Gaussian splats and 3D Tiles are coming together

An exploration of new user interfaces combining geospatial and BIM data from the Bentley iLab team

The Cesium, iTwin, and 3D Tiles track will run through the morning of June 24 and into the morning of June 25.

You can find out more about what’s happening with Cesium and 3D Tiles in the pre-conference Cesium Deep Dive workshop and in mainstage presentations.

An iModel of a Philadelphia Metrostation on top of an iTwin Reality Mesh shown in CesiumJS.

There are six tracks with over 90 full sessions and lightning talks. We’ll be releasing more information about our fantastic mainstage presentations soon, including a closing session that will feature two reality capture stories featured in recent news!

The full agenda for the conference is live. Read more about this year’s tracks on the Cesium blog.

Our speakers are excited to meet up with industry colleagues, share learnings, and hear feedback. Register to attend and connect with the community in Philadelphia. We’ll see you there.

Aerospace, Defense, and Open Geospatial Technologies at the Cesium Developer Conference

Cesium at SIGGRAPH 2026

Help Shape Vector Data Support in 3D Tiles

Bedrock.engineer Streams Subsurface Data at Nation Scale with 3D Tiles Voxels

Advancing 3D Tiles and glTF in an Open Ecosystem

MicroStation Advances Infrastructure Design with 3D Tiles

Cesium at SIGGRAPH 2025

Warfighting, Software, and the OTA