Examples FSharpScript

Example: F# Script Demo

Scripts:

• main_script.fsx
• selection_script.fsx

Use this example when you want to try F# scripting inside Revit.

What It Shows

• referencing Revit API assemblies;
• referencing NuGet packages from a script;
• loading local F# modules;
• creating an IExternalCommand;
• selecting a Revit element;
• printing element metadata;
• trying computational geometry packages such as geometry3Sharp and NetTopologySuite.

Run

1. Open Revit 2025 or adjust the #r paths for your installed Revit version.
2. Add Samples/FSharpScriptDemo/ as a script folder.
3. Run main_script.fsx.
4. Select an element when prompted.
5. Review the trace panel output.

First run may take longer because NuGet packages need to be resolved.

What To Edit

Common edits:

• Change Revit API reference paths for another Revit version.
• Add F# helper code under modules/.
• Try a smaller set of NuGet packages while debugging.
• Replace selection with a collector when you do not need user input.

Troubleshooting

Symptom	Check
Revit API reference not found	update #r paths
NuGet package fails	check package name/version and network access
selection cancels	ESC/cancel is expected to stop the command
command not discovered	file name must end with script.fsx

Related

• Scripting Runtimes
• PEP 440 Versions