Overview
This lecture covers the process of creating a Civil 3D surface from survey points, modifying its display, adding breaklines and boundaries, and preparing the surface for use in design.
Preparing Points for the Surface
- Save your drawing before starting surface creation.
- Create a point group (e.g., "eg topo") with all relevant survey points for the surface.
- Include survey points by group, and use the exclude tab to omit unwanted points (e.g., by number or description).
- Exclude points with descriptions like "inv*" to avoid errors in your surface.*
Creating and Styling the Surface
- In Toolspace Prospector, right-click "Surfaces," select "Create Surface," assign a name, and choose a display style (e.g., 2 foot and 10 foot background).
- The surface is created as a TIN (Triangular Irregular Network), with style controlling contour display.
- Add the prepared point group under "Definition > Point Groups" to let Civil 3D triangulate and generate contours.
Modifying Surface Display
- To change how contours appear, modify the surface style via the ribbon, right-click, or Prospector.
- Set surfaces to "no display" to hide them while keeping them available for calculations.
- Switch styles anytime to view contours, triangles, or both.
Adding Breaklines
- Draw 3D polylines (breaklines) along features like ridge lines if the triangulation does not match real topography.
- Use node osnap or transparent commands to snap polylines to exact points.
- Add breaklines under "Definition > Breaklines," describing and selecting standard type for true 3D lines.
- Standard breaklines use elevation; proximity breaklines do not.
Adding Surface Boundaries
- Turn on all points to review surface coverage and spot invalid triangulation.
- Draw a closed 2D polyline on the correct layer to represent the surface boundary.
- Add this polyline as an "outer boundary" under "Definition > Boundaries" for the surface.
- Select the boundary object when prompted to update the surface clipping.
Key Terms & Definitions
- Point Group — A collection of points managed together for surface creation or exclusion.
- TIN (Triangular Irregular Network) — The base model for surfaces, using triangles between points.
- Surface Style — Controls how surface contours and features are displayed.
- Breakline — A 3D polyline guiding triangulation along specific features.
- Outer Boundary — A polyline limiting the visible and calculated extent of a surface.
Action Items / Next Steps
- Follow the next tutorial to use a data shortcut to share the EG surface in a design drawing for adding alignments and profiles.