Drone photogrammetry and LOD 400 digital twins
Measurable, fully textured 3D models of your asset: RTK-positioned, validated against ground control, and delivered in the formats your design team already runs.
Drone photogrammetry rebuilds a structure or site from thousands of overlapping, RTK-positioned photographs into a point cloud, a textured mesh and an orthomosaic: a digital twin you can measure as well as look at. On structures, Hover captures to LOD 400 detail, so members, connections and fixings are legible in the model. Absolute accuracy is up to 1 cm + 1 ppm horizontal and 1.5 cm + 1 ppm vertical, relative accuracy up to 3–5 mm across a structure, and every model is tested against withheld check points and issued with a Survey Quality Report. Indicative pricing as at October 2026, exclusive of GST: a single-structure twin from about $1,000. Processed models arrive two to three business days after capture, or up to five for large or complex ones.
What lands on your desk
The output is a measurable, textured 3D model: an LOD 400 digital twin accurate enough for engineering, delivered in the formats your design software already reads. Every capture is processed into a validated model set and packaged with a Survey Quality Report, so your engineers can check the accuracy for themselves.
| Textured mesh | .OBJ / .FBX |
|---|---|
| Point cloud | .LAS / .RCP |
| Orthomosaic | GeoTIFF |
| Surfaces | DTM / DEM |
| Validation | SURVEY QUALITY REPORT — PDF |
MESH DETAIL — LOD 400Which file opens where
A twin is only useful if it opens on the machine of the person who needs it. Each format is cut for a job, and the set is agreed at scoping so nobody spends a morning converting files.
| Point cloud — .RCP | Autodesk ReCap format: indexed for Revit, Civil 3D and Navisworks |
|---|---|
| Point cloud — .LAS | The open standard: 12d, Trimble Business Center, OpenRoads and GIS platforms |
| Textured mesh — .OBJ / .FBX | The photoreal model, for inspection review, visualisation and context models |
| Orthomosaic — GeoTIFF | A georeferenced image for GIS, or as a base under your CAD design |
| Surfaces — DTM / DEM | Terrain for design and earthworks in Civil 3D, 12d and OpenRoads |
How the accuracy is tested
RTK corrections tie every image to survey control as it is captured: up to 1 cm + 1 ppm horizontal and 1.5 cm + 1 ppm vertical. Ground control points constrain the model, check points withheld from the bundle adjustment test it, and both sets of residuals go in your report.
On structures, relative accuracy is up to 3–5 mm, which is what matters for clearance checks, deformation baselines and fit-up.
Every survey is issued against an accuracy gate set for that job and stated in the proposal before capture. If the data does not meet it, ground control is re-marked and the aerotriangulation re-run; if it still falls short, the site is re-flown at no cost to you.
The Survey Quality Report that ships with the data carries the aerotriangulation results, reprojection error, GCP residuals, check-point Z-residuals and the RMSE summary.
Photogrammetry needs to see the surface. Dense canopy and open water break reconstruction, and if your site has either we say so before the flight is booked.
| Horizontal accuracy | Up to 1 cm + 1 ppm |
|---|---|
| Vertical accuracy | Up to 1.5 cm + 1 ppm |
| Relative (structures) | Up to 3–5 mm |
| Validation | WITHHELD CHECK POINTS, EVERY JOB |
CONTROL OVERLAYWhat LOD 400 means for a captured model
LOD is a level-of-development scale from BIM practice. At 400, a model element carries enough geometry to fabricate from: individual members, connections and fixings, not just the overall shape. A model captured from a real structure earns that label when those details are legible and measurable in the twin itself, which is what the comparison below shows.
LOD describes how much reliable detail a model element carries. How accurately a captured model is positioned is a separate question, answered by the accuracy gate stated in every proposal and tested at the withheld check points. A twin can be rich in detail and still sit in the wrong place, which is why the two are reported separately. How a twin pays for itself on a project is covered in what a digital twin is and how it saves money.
The twin holds up at rivet scale
Left: the drone photograph. Right: the same truss node inside the LOD 400 model.
SITE PHOTO
DIGITAL TWIN — MESHStructures a twin earns its keep on
Bridges and rail structures
Trusses, girders, bearings and piers captured member by member, including the soffit faces a ground crew never sees, for remediation scoping, clearance checks and a condition baseline.
Culverts, headwalls and spillways
Concrete hydraulic structures recorded at a resolution that shows surface condition as well as shape, and the base for AI defect detection when cracking has to be counted.
Towers, plant and facades
Measured geometry for retrofit design and fit-up at height, without a climb crew. Where only a condition record is needed, a close visual inspection costs less.
Whole sites rather than single structures are usually better scoped as a drone topographic survey, and anything measured in cubic metres belongs with stockpile and volumetric surveys.
Structures across South East Queensland are flown from the Brisbane base, including controlled-airspace sites in the city covered under drone 3D mapping in Brisbane; site, stockpile and progress work in the city is scoped through drone surveying in Brisbane. Anything in regional Queensland or Northern NSW is booked as a scheduled regional job, with travel built into one fixed price.
Where photogrammetry beats a ground crew, and where it does not
A drone captures the full asset in hours — every face, every elevation, the roof nobody has photographed since construction — from safe standoff, with no plant hire and no working-at-height exposure. The result is a complete, revisitable record rather than a folder of point measurements. Pair the capture with AI defect analysis and the same imagery is screened for cracking, with every detection verified by hand.
It's not the tool for everything. Under dense canopy a ground survey wins, and canopy is also where LiDAR most clearly beats a camera; the trade-off is set out in photogrammetry vs LiDAR for civil construction. And boundary or cadastral work is legal survey territory: it belongs with a registered surveyor, and we refer it.
Four steps from flight plan to delivery
- 01
Flight and control plan
Capture geometry, GSD and GCP layout designed around your accuracy spec and site constraints.
- 02
RTK capture
Base station on known control; every frame position-stamped at capture.
- 03
Reconstruction and validation
Model built on the control points, then tested against withheld check points. Residuals recorded.
- 04
QA and delivery
Formats cut to your stack, with the Survey Quality Report attached.
Questions we get at scoping
Q/01How accurate is drone photogrammetry?
With RTK corrections and ground control validation, our surveys achieve up to 1 cm + 1 ppm horizontal and 1.5 cm + 1 ppm vertical accuracy, with up to 3–5 mm relative accuracy on structures. Every delivery includes the Survey Quality Report showing the residuals, so the accuracy claim can be checked.
Q/02What is an LOD 400 digital twin?
LOD 400 is a level-of-development standard from BIM practice: the model is detailed enough to measure fabrication-level geometry (individual members, connections, fixings), not just overall shape. It means your engineers can take dimensions from the model with confidence instead of revisiting site.
Q/03What software does the data work with?
Deliverables drop straight into Civil 3D, 12d, Revit, OpenRoads, Trimble Business Center and standard GIS platforms. We cut .LAS, .RCP, .OBJ, .FBX, GeoTIFF and DTM/DEM surfaces to suit your workflow, with no conversion step on your side.
Q/04How long until we receive the model?
Most single structures are captured in one site visit. Processed models are issued two to three business days after capture, or up to five for large or complex models, and each arrives with its Survey Quality Report; we do not release unchecked models.
Q/05Do you use LiDAR?
No, we run photogrammetry. For textured, inspectable digital twins at this accuracy class, photogrammetry delivers the visual detail LiDAR cannot: every rivet, stain and visible crack is in the model, not just its geometry. Where a project needs LiDAR, we say so at quoting.
Q/06Does the structure need to close for capture?
Rarely. Capture is flown from standoff, so most bridges, towers and buildings stay in service while it happens. Rail corridors are different: the work is planned inside the owner's possession and protection arrangements, as it was for Hover's close visual inspection of the Indooroopilly Rail Bridge.
Q/07Can you capture the underside of a bridge deck?
Yes, wherever the soffit can be seen and safely flown. Under-deck faces, bearing shelves and truss interiors are captured from standoff, and the flight plan is built around the clearance the structure allows.
Q/08How much does a drone digital twin cost?
A single-structure LOD 400 digital twin typically starts around $1,000, exclusive of GST, and rises with size, complexity and access. See the drone survey cost guide for how the number is built up; Hover quotes each job in writing within one business day.
Scope this for your site
Send the asset and the deliverable you need. A scoped method and quote come back within one business day.
HARRY BILLING — CHIEF REMOTE PILOT
0411 445 458
[email protected]
CASA ReOC #9398 · $28M PUBLIC LIABILITY