A starter kit for developing web applications for infrastructure digital twins.


Simple and quick delivery of infrastructure digital twins

Jump start your ability with a set of APIs and sample code.

If you are developing infrastructure digital twins for the first time, iTwin.js will help you get web applications up-and-running quickly.

Why digital twins?

Infrastructure professionals are quickly catching on to the significant gains that can be realized by digital twins with more than half of all large industrial companies expected to use digital twins in some form by 2021.

The concept of an infrastructure digital twin is simple. If you have a physical asset and a digital asset that can represent everything in the physical asset, you can join them together, then use the digital asset to understand what is happening with the physical asset in the real world.

How digital twins?

The data required to create a digital twin is in different data repositories from different vendors in incompatible formats, and is constantly changing. It can’t be easily aggregated or visualized. We know this can be daunting. Now, there is an easier way.

With iTwin.js, you have a powerful starter kit and access to a community of experts to help you tackle the most difficult digital twin challenges. Everything you need to get started.

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The concept of digital twins is about connectedness. The aim is to bring infrastructure data together, crossing the boundaries of formats, servers, IT silos, politics, and hierarchy.

Federate and align files such as specs, drawings, documents, and BIM models of any size, in their native engineering formats.


Show BIM data, reality data, GIS, and IoT data streams in a single pane of glass.

Visualize and analyze engineering change in 3D and 4D using a standard web browser.

Offer robust tools for viewing, interrogating, and leveraging your digital twin.

Control Change

Provide an accurate record of who-changed-what-when.

Services and applications can obtain a copy of the digital twin and subscribe to notifications of changes added to the timeline. Upon notification, they receive changes and apply them to their local copy of the digital twin, thereby synchronizing it. Use change notification system to drive automated digital workflows.

Everybody says “open.” But there aren’t degrees of openness—either you mean it or you don't. Is your technology designed in a manner that the option to switch vendors is foreclosed or not?

Ensure your data is not locked into a single vendor solution. Have the ability to import and export data freely.

When you write an application with iTwin.js, it can run anywhere. It doesn’t have to run in any specific cloud. It doesn’t force you to store your data in a cloud that is constrained by Terms of Service.

Your data will not be aggregated, analyzed, or used by third parties to generate proprietary insights.

You will always be able to access your data and get your data out.

Open source and open data mean that you retain control and flexibility.

Before you start.

What you need to know.

Digital twins have the potential for millions of use cases. No one knows what a digital twin is going to be like five years from now. No single vendor can possibly address all those use cases or foresee how those use cases will evolve. Our industry wants the flexibility to change as requirements change and as things become possible that were not possible before.

So, it is important to design applications with flexibility in mind. In software terms, that means open.

Infrastructure professionals want the flexibility to take data and combine it with other data sources, send it to other systems, or give it to another vendor to have them write some software.

Creating a digital twin does not require stopping anything that you are already doing. Once your users are more familiar with digital twins, they may decide to stop doing manual processes, such as creating pdf files. They will be much happier if you start with a successful project and adapt from there rather than trying to switch everything at once.

What to look for in a digital twin platform?

Keith Bentley, CTO of Bentley Systems, Inc. discusses the key elements of an open digital twin platform.

iTwin Developer Conference

Watch the inaugural iTwin Developer Conference. This event brought together the growing community of infrastructure digital twin developers and thought leaders—including Keith Bentley and experts from Siemens, Microsoft and more!

Deep Dive: Integrating 3D Models and IoT data with iTwin and Azure Digital Twins

In this session we will demonstrate an application that combines 3D models, 2D maps, and reality mesh into a single environment for visualization. Within that environment we will demonstrate a live, real time, seamless visualization of IoT data streams. Next we will walk through the architecture that enables the application. We will show how we have mapped the IoT data to the assets within the digital twin. And we will show how to keep the digital twin in step with engineering changes. This is done by automating the generation of the Digital Twin Description Language (DTDL) JSON.

Developer Workshop

Learn how to build apps for infrastructure digital twins. Bentley's development team shows you how. Watch on-demand

What is an iModel?

An iModel is a specialized information container for exchanging data associated with the lifecycle of infrastructure assets. iModels are self-describing, geometrically precise, open, portable, and secure. iModels were created to facilitate the sharing and distribution of information regardless of the source and format of the information.

Project teams use iModels to ensure that information flows easily, completely, and accurately between and within design, construction, and operations environments.

iModels encapsulate component information, including business properties, geometry, graphics, and relationships in a format that is open, providing standard interfaces for business, engineering, construction, and operations applications from multiple vendors.

iModels are an essential part of the digital twin world. But a digital twin means a lot more than just an iModel. A digital twin means a vast ocean of federated data sources, one of which will be an iModel.

If you are creating a digital twin of an infrastructure asset, you are going to need a lot of data from many sources. Some of it is going to come from engineering applications and you need a place to store it. That’s what iModels are for. iModels are specialized information containers.

The original goal of iModels was a sort of zip file. Collect all your engineering data, put it in one place, now you can find it. But we discovered there were two fundamental issues with that approach.

One was you put a copy of the data into the zip file and as soon as you change it, you have to recreate the entire .zip file. Now you have two .zip files. Which one is right?

And if I emailed you a copy of the .zip file, I’ve got to make sure you delete it so that you don't use the wrong data. Change happens, and the original iModel concept didn't account for that.

The essence of a digital twin is it reflects reality and reality always changes.

Second, it is valuable to know where to find data. But once you find it you need to interpret it. Each application has a specific native format and you shouldn’t have to go back to the design tool that was used to author it in order to understand the format.

iModel 2.0 addresses both of those issues. It takes data from source applications and maps it into a normalized schema that we can see.

We figured out what was common among the known universe of schemas (e.g. IFC, DGN, DWG, RVT, et al.) and we created a way to store data in one place and index it.

A big part of iModel 2.0 is the normalized schema that we map data to when we import it. It is very liberating because you no longer need to be concerned about which application created the data to consume the data.

The second thing about iModel 2.0 is when you modify data, you don't have to regenerate your entire digital twin, and worry about which version you are looking at.

iModels are now designed with the knowledge that their content will be modified externally and will be synchronized using a service called iModelHub.

iModelHub has three functions. It maintains the sequence of change sets that build up the timeline of change. It accepts change sets and notifies users of change. It coordinates concurrent access.

Alignment and change tracking are two very important capabilities for the theory of the digital twin.

Community of infrastructure digital twin developers

We aim to foster a thriving community of developers who share our vision of creating infrastructure digital twins.

Our goal is to help transform our understanding of the world’s infrastructure, optimize its performance, and improve its resilience.

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