Go to the tab. Start with a Sequence (this holds all your points). Add the following Point definitions (use the "Geometry" toolbox):
Points can be defined by delta X and delta Y, slope and delta X, or intersections.
The canvas where you construct the logical sequence of your subassembly. Components connect sequentially to establish how Civil 3D reads and builds the geometry.
: Shows how the component looks inside Civil 3D before a corridor is built. Subassembly Composer Autocad Civil 3d Tutorial Pdf
Autodesk Subassembly Composer (SAC) is a standalone application that allows you to create complex, parametric subassemblies for AutoCAD Civil 3D without needing advanced programming skills
Autodesk Subassembly Composer provides an interface for composing and modifying complex subassemblies without programming. It is an easy-to-use authoring tool used to create custom components to solve complex grading challenges, detail construction plans, and get accurate quantities.
Short intro paragraph: Subassembly Composer (SAC) enables custom subassemblies for AutoCAD Civil 3D corridors by letting users define points, links, parameters, and logic graphically. Custom subassemblies help model complex cross-sections not available in the out-of-the-box library. Go to the tab
Which the subassembly needs to follow (e.g., surface targets, horizontal alignments).
Force points to follow a specific 2D alignment, feature line, or survey figure horizontally.
The canvas where you map out the logic of your subassembly. It uses a top-down, tree-like structure to establish the execution order of points and links. The Preview Panel The canvas where you construct the logical sequence
Points are the exact coordinate vertices of your geometry. The first point ( P1 ) always defaults to the , which represents the attachment point along the Civil 3D baseline assembly.
is a powerful standalone software application that works alongside AutoCAD Civil 3D . It allows civil engineers, designers, and road modelers to create custom subassemblies for corridor models. Unlike standard subassemblies from Civil 3D’s tool palettes, custom subassemblies give you complete control over parametric behavior, target mapping, and conditional logic (e.g., "if slope > 2:1, add a ditch").
The Subassembly Composer is a standalone application installed alongside Autodesk Civil 3D. It allows engineers and designers to create complex custom subassemblies visually, using flowchart logic, without requiring advanced .NET programming knowledge. Why Use Subassembly Composer?