This reference covers what a surveyor needs to deliver for the Dusty FieldPrinter to station accurately: how many control points to set, where to place them, how to mark them, and the required CSV format. Use it when planning your control network and preparing your deliverable before layout begins.
Why Control Quality Matters
The FieldPrinter does not guess or stretch the layout to fit. The laser tracker references multiple control points to best-fit the digital layout file to the slab, so the quality of the survey deliverable directly sets the ceiling on layout accuracy. Bad control shows up as high error and difference values during stationing — a control issue, not a robot issue.
Minimum Requirements
| Requirement | Specification |
|---|---|
| Minimum points per station | 3, non-collinear (never all on a single straight line) |
| Recommended points per station | 3 or more |
| Survey accuracy tolerance | 1/16" recommended — adjust to your project's required tolerance |
| Horizontal coordinates | X and Y always required |
| Vertical coordinate (Z) | See "Z Coordinate Requirements" below — depends on your radio |
| Coordinate system | Must match the layout file coordinate system exported from AutoCAD to the Dusty Portal |
| Delivery format | CSV, DWG markup, or PDF markup (see "Accepted Deliverable Formats" below) |
| Instrument | No specific brand required — all control must resolve to accurate coordinates |
Placement and Geometry
More points and wider spacing both improve the best-fit calculation and reduce the influence of any single bad point.
- Spread points as far apart as possible. Any shape or random arrangement works — they just cannot all fall on one straight line. Collinear points degrade stationing accuracy.
- Surround the print area. Place points around the perimeter of the intended work area, not clustered inside it or on one side.
- Favor distance. Distance from the laser tracker matters as much as the error value. A point 10' away with 1/16" error can perform worse than a point 100' away with 1/8" error when the print area extends to 100'.
- Elevations can differ. Control points do not all need to sit at the same Z-height. When elevations vary, your Z coordinate obligations depend on the robot's radio — see below.
- Plan for re-stationing. The tracker may be re-stationed multiple times as the robot works around columns, walls, and material. Set enough points that every station position has 3+ visible, well-distributed points.
Z Coordinate Requirements
Whether you need to provide Z (elevation) coordinates depends on which radio the FieldPrinter is using:
| Radio | Z coordinate requirement |
|---|---|
| Radio 2 | Z is optional |
| Radio 1 | Z is required in the CSV when control point elevations differ from one another |
If you are not sure which radio is on site, confirm with the operator or your Dusty contact before finalizing the deliverable.
Physical Marking Requirements
| Attribute | Requirement |
|---|---|
| Mark | Crisp "X" or target mark on the slab |
| Label | Legible, and matching the point name in the CSV exactly |
| Surface | Avoid slab cracks, spalls, and unfinished areas |
| Durability | Points must not move, get covered, or be ground off during construction |
For wall/column control, permanently mounted drift nests are one of the most accurate options and give the strongest station-to-station consistency. Nests must be rigidly attached — not loose or spinning.
Accepted Deliverable Formats
You can deliver control in any one of these formats. All must use the same coordinate system as the layout file.
1. CSV file (uploaded to the Dusty Portal)
Include a header row with these column names:
Point Name, X, Y, Z, Description (optional)
- Coordinate column order may be X, Y, Z or Y, X, Z.
- Include Z per the Z Coordinate Requirements above.
2. Control point markup in DWG
Mark the control point locations in the drawing, indicating either the point coordinates or the offset distances from reference objects (such as grid lines).
3. Control point markup in PDF
Same as the DWG option — indicate either the coordinates or the offset distances from reference objects (such as grid lines).
If the survey team can only provide CAD points and you want a CSV, two conversion paths exist: the LSP Control Export Tool (available in Dusty Academy) or AutoCAD Data Extraction to export point coordinates to CSV.
Coordination Checklist (Before Layout Begins)
- Align expectations between the surveyor, VDC, and field teams on the control network and coordinate system.
- Share onsite control point pictures with the Dusty team before implementation.
- Confirm all trades will reference the same control network.
- If multiple points show high error during stationing, request surveyor verification — bi-pod workflow tolerance can reach 1/8"–3/4" depending on technique.