Lot & Zones Grading

After 2D and 3D checks are complete, Lot & Zones Grading opens an interactive modal where you assign presets, submit jobs to the grading engine, and review results — all without leaving Civil 3D.

Prerequisites

Complete the 3D Checks step before running this command. The lot grading process requires permanent 3D feature lines in the drawing.

Run the command

Type LOTZONEGRADING in the Civil 3D command line, or click the Lot & Zones Grading button in the Core Tools panel of the DRTWRK Tools ribbon.

Step 1 — Open the grading viewer

The grading viewer opens alongside your Civil 3D drawing. Your subdivision appears on screen with all lots, zones, and road geometry.

If the subdivision does not look correct:

Problem	What to check
Missing lots	Are all lot boundaries closed? Is the correct layer selected?
Nothing showing	Were all issues resolved in 2D and 3D processing?
Property line missing	Is the property line a single closed line on its own layer?

Step 2 — Assign presets

Every lot and zone needs a preset assigned before grading can begin. drtwrk organizes your file into two types of grading units:

• Lot Group — a set of residential lots with no adjacent zone
• Area — a lot group combined with one or more adjacent zones, graded together so shared boundaries connect correctly

Same preset for all lots in a group:

1. Click the lot group on screen
2. Click Assign Preset, select a preset, and click Confirm

Different preset per lot:

1. Click an individual lot on screen
2. Click Assign Preset, select a preset, and click Confirm
3. Repeat for each lot

For areas with zones, assign a preset to each zone as well — the Submit to Grade button is not active until every lot and zone has a preset assigned.

Step 3 — Submit to grade

In the modal, review and adjust grading parameters — grade limits, slopes, cut/fill preferences — then click Submit. The plugin:

1. Updates feature lines in Civil 3D to reflect any elevation changes you made
2. Creates a grading job in the drtwrk cloud
3. The grading engine calculates lot grading elevations
4. A new TIN surface is created in Civil 3D
5. Updated feature lines are added to the surface as breaklines
6. Spot elevations and slope labels are placed on the surface

Grading not finishing?

Wait the full 2 minutes. If nothing happens, click Submit to Grade again. If it still does not complete, note which lot group or area you were grading and report it.

Step 4 — Review results

The grading viewer displays results directly on your subdivision:

Element	Description
Elevation numbers	Height at each point along lot lines
Slope percentages	Slope on each lot line segment
Swale lines	Where water flows along shared boundaries
Walls	Retaining or stem walls placed by the grading engine
Drain inlets	Inlets at low points where rear drainage is enabled
Grading summary	Pass/fail status for each constraint per lot

Review checklist:

• Slope values are within the preset limits
• Setback distances are respected
• Retaining walls are placed correctly
• Stem walls are placed correctly
• Drain inlets are at the low points of the lot, not the high points
• Finished floor elevation is consistent with the road elevation

Step 5 — Measure distances

Use the measurement tool to verify distances — for example, to confirm a setback matches the preset value.

1. Click the Measure tool in the toolbar
2. Click a starting point on screen
3. Click an ending point — the distance between the two points appears

Step 6 — Reposition labels

If labels overlap at lot corners, swale intersections, or drain clusters:

1. Click any label
2. Drag it to a new position

Step 7 — Make manual adjustments

1. Click any element — a lot line, elevation point, or slope value
2. Change the value
3. The viewer updates to reflect the change

Step 8 — Compare solutions

If you assigned different presets to lots within the same lot group:

1. Click the lot group
2. Click Solution Comparison Table
3. Review slope values, wall usage, drainage, and pass/fail status across all solutions
4. Select the solution that best fits your project

Length tolerance settings

Setting	Default	Description
MinIssueLengthToFlag	Drawing point tolerance	Issues shorter than this value are not flagged. Not adjustable.
MaxIssueLengthToFlag	1.5 m	Issues longer than this value are not flagged

Grading data is persisted across drawing sessions using a unique file ID stored inside the drawing. If you rename or move the drawing file, the plugin uses this ID to locate the correct data — you do not need to reprocess from scratch.

Next step

When you are satisfied with the results, proceed to Export to Civil 3D.