Delft3D Flexible Mesh Suite
The Delft3D Flexible Mesh Suite (Delft3D FM) is the successor of the structured Delft3D 4 Suite. Like Delft3D 4, the Delft3D FM Suite can simulate storm surges, hurricanes, tsunamis, detailed flows and water levels, waves, sediment transport and morphology, water quality and ecology, and is capable of handling the interactions between these processes. The suite is designed for use by domain experts and non-experts alike, which may range from consultants and engineers or contractors, to regulators and government officials, all of whom are active in one or more of the stages of the design, implementation and management cycle.
How to get Delft3D FM?
Delft3D Flexible Mesh (Delft3D FM) is open-source software. To access the source code of Delft3D Flexible Mesh follow the steps listed below. Technical support and the latest pre-compiled fully validated release are available via Deltares USA Delft3D Service Packages. You can order the service package of your choice via software@deltares-usa.us or request a Service Package here.
Note (May 2026 update): Deltares moved the Delft3D FM source code from Subversion (SVN) to Git in 2024. The old SVN repository at `svn.oss.deltares.nl` is no longer the active source. All current development happens on GitHub.
How to access and compile the open source Delft3D FM software :
1. Create a My Deltares account
A My Deltares account is still useful for the community forum, FAQ, and pre-built binary downloads, but is no longer required to access the source code.
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- Go to https://oss.deltares.nl
- Click "Create Account" in the upper right
- Fill in the form
- You will receive an email with a verification link and your account credentials
2. Get the source code from GitHub
The repository lives at: https://github.com/Deltares/Delft3D
The `main` branch is the primary development line. Tagged releases (for example, 2026.02, released 28 April 2026) provide stable starting points for reproducible work.
Background and additional details are at the official Deltares get-started page: https://oss.deltares.nl/web/delft3dfm/get-started.
The two SVN revisions previously listed on this page correspond to the following releases on GitHub:
- v43444 applied by Martyr et al. (2017) and Vroom et al. (2017)
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v66357 (2020.04 release; April 11, 2020) applied by Nederhoff et al. (2021)
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2024.03 release applied by Nederhoff et al. (2025)
3. Using the program
We cannot cover all of the steps for using the program here. But these links contain all information needed:
Compile the code using the instructions here. The current manual is available here. You may have some success obtaining help from the forum community.