Learn how to create subassemblies that meet your specific design requirements.
The Autodesk Subassembly Composer for
Autodesk Civil 3D is installed with
Autodesk Civil 3D 2025. It provides an interface for composing and modifying complex subassemblies, without a need for programming.
For more information, see the Autodesk Subassembly Composer Help.
Subassembly developers can compose complex subassemblies visually, using a powerful yet easy-to-use interface:
- Define the behavior of a subassembly using an easy to understand flowchart.
- Drag and drop common geometry elements and conditions from the categorized a tool box onto the flowchart.
- See a preview of the subassembly geometry, and simulate how the subassembly behaves with different target values and conditions.
- Find and edit the properties of a subassembly element using the synchronized flowchart and preview.
- Attach help documentation to the subassembly.
- Save subassemblies as PKT files. The PKT files can be imported into Autodesk Civil 3D, which automatically generates ATC files.