When sharing subassemblies with teammates, use clear naming conventions for points, parameters, and decision branches. Well-documented flowcharts are far easier for colleagues to understand and enhance.
In the Expression field, write an IF/THEN statement. For target checking, use: BaseSurface.IsValid .
Civil 3D Subassembly Composer is a powerful tool for civil infrastructure designers. It allows you to create custom subassemblies that handle complex corridor modeling scenarios beyond the capabilities of standard out-of-the-box Civil 3D components.
Click inside the closed loop of links (L1, L2, L3... down to the subgrade links) in the Properties panel to define . Label the code field "Pave1" . 5. Working with Advanced Logic: Decisions and Targets
This tutorial walks through creating a simple custom curb to understand the workflow. Step A: Define Input Parameters Open SAC and go to the tab. civil design 3d subassembly composer tutorial pdf top
Select your links (like the top of the curb) and enter "Top" in the Codes field. Always use quotation marks around code names in SAC. Select the bottom links and code them as "Datum" . Select your shape and code it as "Concrete" . Saving and Importing
Start with the Autodesk official user guide (the free PDF). Then, build the simple lane example in this article. Finally, download one of the AU class handouts listed above. Within a week, you will move from searching for "top PDFs" to writing your own company training documents.
Professional tutorials typically follow this six-step workflow to ensure stability and accuracy: Subassembly Composer Pt. 1 - Exploring the Interface
To download the Civil Design 3D Subassembly Composer tutorial PDF, simply click on the link below: When sharing subassemblies with teammates, use clear naming
Basic geometry is straightforward, but real-world conditions require advanced decision structures.
Under the branch, build your daylight geometry targeting the surface.
The core philosophy of Subassembly Composer is to make custom subassembly authoring accessible to all Civil 3D users. Instead of writing code, you build logic using a drag-and-drop flowchart that defines geometry, conditional behaviors, and dynamic targeting. When you need a subassembly that doesn't exist in the Civil 3D tool palette, SAC empowers you to create exactly what your design requires.
Create parameters: CurbWidth (Double), CurbHeight (Double), Side (Side). Step B: Building the Geometry (Flowchart) For target checking, use: BaseSurface
Go to the tab and create a target named Existing_Surface (Type: Surface). Use the Advanced Geometry tool called Intersection Point .
| Parameter Type | Name | Default Value | Purpose | |---|---|---|---| | Double | LaneWidth | 12.0 (ft) | Lane width from centerline | | Double | LaneSlope | -2.0 (%) | Cross-slope of lane | | Double | ShoulderWidth | 4.0 (ft) | Width of shoulder | | Double | ShoulderSlope | -4.0 (%) | Cross-slope of shoulder | | Target Surface | DaylightSurface | None | Surface to daylight to |
Never import a subassembly into Civil 3D without testing it thoroughly inside Subassembly Composer first. Validation Checklist