2D Checks
2D Checks is the first step in the drtwrk workflow. It validates and cleans your 2D CAD geometry, identifies issues that need to be resolved, and prepares your linework for the 3D step.
Before you begin
Make sure your file includes the following before running this command:
- Lot lines are present and correct in the drawing
- If your lots are closed by a property line boundary, the property line is present and in 2D
If you're including a property line, it must have elevations assigned to it. Project it onto your road surface in Civil 3D before continuing. A property line without elevations will cause grading issues.
Run the command
Type 2DLINEWORK in the Civil 3D command line, or click the 2D Checks button in the Core Tools panel of the DRTWRK Tools ribbon.
Configure layers first
Before running, open the Layer Review modal to map each CAD layer to the correct geometry type.
| Layer Type | Required | Description |
|---|---|---|
| Lot Lines | Yes | The boundary lines of each individual lot. Every lot must be fully enclosed. |
| Right of Way (ROW) | Yes | The legal boundary line along the side of the road. |
| Road Centerline | Yes | The line running down the center of each road. |
| Curb | No | The curb line along the edge of the road. |
| EOP (Edge of Pavement) | No | The line where the road surface ends. |
| Edge of Swale | No | The swale line along the road. |
| Property Line | No (if applicable) | The outer boundary of the entire property. Must be a single closed line on its own layer. |
| Pond Top of Bank | No (if applicable) | The grading boundary line around a pond. Must be on its own layer with nothing else on it. |
Hover over any line in your drawing to see its layer name in the Civil 3D status bar.
Lots can be enclosed by lot lines, a property line, a right-of-way line, or a sidewalk line. drtwrk handles all of these automatically.
What the tool does
Once you run the command, the plugin performs the following operations:
- Collect objects — selects all objects from the layers configured in Layer Review
- Split lines at intersections — divides lines wherever they cross so the network is correctly connected
- Clean data — removes duplicate points and short segments
- Build node adjacency graph — constructs a graph describing which lines connect to each other
- Identify errors — flags overlapping lines, open endpoints, and short segments
- Export data to JSON — serializes the processed geometry for the drtwrk grading engine
Review and fix errors
After processing, the Grading Prep Review panel opens and lists all detected issues. Every issue must be resolved before moving forward.
| Action | Description |
|---|---|
| Focus | Zooms the Civil 3D viewport to the location of the issue. |
| AutoFix | Attempts to repair the issue automatically. |
| Dismiss | Marks a single issue as ignored. |
| Dismiss All | Marks all issues as ignored. |
| Reprocess | Re-runs error detection after you have made manual edits. |
| Submit | Finalizes the 2D step and advances to 3D Checks. |
For issues requiring manual edits, zoom into the flagged area in Civil 3D, make corrections, save the file, then click Reprocess.
Common 2D issues
| Issue | What it means | How to fix |
|---|---|---|
| Lot Line Underhang | A gap in the lot boundary — lines don't fully close | Use AutoFix or snap the endpoint manually |
| Lot Line Overhang | A lot line extends beyond its endpoint | Use AutoFix or TRIM in Civil 3D |
| Duplicate geometry | Two lines on top of each other | Delete one of the duplicates |
| Missing layer | A required layer was not found | Verify the correct layer name is selected |
If your file has a large number of discrepancies, working through them may take some time. A clean starting point directly controls the accuracy of the grading output.
Processing tolerances
After reprocessing, drtwrk prompts you to set tolerances that control which issues get flagged:
| Tolerance | Default | Adjustable | Description |
|---|---|---|---|
| Maximum issue length to flag | 1.5 m | Yes (up to 1.5 m) | Issues longer than this are not flagged |
| Maximum overlap tolerance | 1 m | Yes | Overlaps within this distance are flagged |
| Minimum issue length to flag | Drawing point tolerance | No | Issues shorter than this are never flagged |
Lower the maximum values to flag fewer, larger issues; raise them to catch more. The minimum is not a setting — it is taken from your drawing's own point tolerance, so anything below it cannot be distinguished from two points being in the same place.