3D site monitoring: the guide for project owners and project managers
By Olivier Kerremans ·
Traditional site monitoring relies on scattered photos, written reports, and repeated travel. It is inefficient for remote stakeholders (architects, project owners, specialised subcontractors) and it is a source of disputes when the memory of “what was done when” becomes blurry.
Documenting a site in photorealistic 3D, at regular intervals, changes the game. Here is a practical guide for project owners, project managers, BIM and VDC leads, and QHSE coordinators who want to understand what this approach brings concretely, and how to put it in place.
The problem with traditional site monitoring
Three structural frictions have existed for a long time.
Scattered photos. Several people take photos with their phones, which end up in shared drives, WhatsApp channels, or never centralised. Coverage is haphazard, quality variable, and finding “the photo of the north-west corner, week 12” is a feat of archaeology.
Multiplied travel. On a large site, several stakeholders work remotely. Architect, project owner, inspection office, specialised subcontractors. Each physical visit costs time, expense, and is not always possible at critical moments.
Disputes over the real state. When a dispute arises about what was done at a given date, the existing documentation is rarely precise enough to settle it. Photos taken at a poor angle, incomplete reports, faulty memory. Arbitration is done on the basis of a file that was not compiled for that purpose.
What photorealistic 3D site monitoring changes
3D Gaussian Splatting (see our complete guide to 3DGS) makes it possible to capture a site in a few minutes to a few hours, and to deliver a navigable 3D model within 24 to 48 hours. Three direct benefits.
A 3D model navigable by everyone
No app, no software, no training. The project owner clicks a link and navigates freely through the site from their desk. The architect checks the execution of a technical detail without travelling. The subcontractor briefs their teams by showing exactly where they will work.
A comparison between two dates
Successive captures are aligned to the same reference. You switch from a “week 8” state to a “week 12” state and you see the evolution. No more “I think it was done before Easter”; the question is settled in three clicks.
Probative documentation
If a dispute arises, you have a time-stamped, photorealistic, navigable and incontestable state. This legal value transforms the nature of the site archive. It is no longer a folder of photos; it is an opposable reference.
3DGS capture on site, how it works
For a project manager who has never seen a 3DGS capture, here is what a typical visit looks like.
Before the visit
We agree on the area to cover (a whole floor, a slab, a facade, technical rooms) and the slot. A capture can be done with teams at work, without interruption. The site coordinator is informed but loses no time.
During the capture
With a specialised ground camera, the area is walked through in continuous motion. No tripod, no pose, no marking out. The camera records hundreds to thousands of images from varied angles. For a 500 m² area, count on 30 to 60 minutes of effective capture.
Standard PPE, helmet, safety shoes, high-visibility vest. No particular constraint beyond that.
After the capture
The data is brought back, processing is done on the GPU. The final model is delivered within 24 to 48 hours via a web link. All the stakeholders concerned receive this link, open it, and navigate.
How often should you capture a site?
The right frequency depends on the type of site and the phases. Here is a practical guide.
Structural-works site, monthly
Changes are visually striking but spaced out. One capture a month is enough to document the progress of load-bearing elements (foundations, slabs, walls, framework).
Fit-out site, fortnightly
Partitions, technical ducts, finishes. Changes are fast and some become invisible as soon as they are enclosed in a partition. A capture every two weeks is a good rhythm.
Critical phases, event-driven capture
Before a major pour, before closing the technical ducts, before installing the ceilings, before delivering a batch. At those moments, an additional capture between two regular visits guarantees that the state is documented before it becomes inaccessible.
Edge case, heritage renovation site
On a listed or heritage site, a capture before works is essential. It forms the reference of the initial state, opposable in the event of disagreement with the heritage services.
Who uses the 3D model and for what?
Five profiles draw a direct benefit from 3D site monitoring.
Project owner
Remote monitoring of progress, quarterly reporting to a steering committee with a link in the PDF, visual verification of the invoiced works. A reduction in the number of physical visits, without losing control of the file.
Architect
Verification of the execution of technical details (junctions, layout, finishes), remote validation of the executed material choices, an archive of the built work for the agency’s portfolio.
Subcontractors
Visual briefing of teams before intervention, precise reading of the arrival context (clean site or not, access, surrounding elements), prevention of conflicts with other trades.
QHSE and inspection office
Remote safety audit, verification of the compliance of temporary installations (scaffolding, guardrails, signage), documentation for the weekly safety meetings.
Engineering office
Verification of compliance with the drawings, comparison between the executed and the planned, feeding a richer as-built file than a simple set of drawings.
3D site monitoring and BIM, complementary or competing?
A frequent question. A clear answer: complementary.
3DGS does not replace BIM
BIM is a structured, intelligent, manipulable model that contains domain data (materials, performance, schedule, costs). 3DGS is a photorealistic capture of the real state at a given moment. These are two objects of different natures.
How the two feed each other
BIM describes what should be. 3DGS documents what is. Comparing the two at regular intervals lets you detect gaps, qualify non-conformities, and feed the as-built BIM with an indisputable visual reference.
Cases where 3DGS brings what BIM cannot
The BIM model does not always reflect reality. Changes decided on site, unforeseen adjustments, execution defects. 3DGS captures this reality without a filter. It is valuable for the project owner who wants to know what what they are buying really looks like.
Conversely, for precise metric surveys or to feed an IFC file, 3DGS is not the right answer. A laser scan is better suited. 3DGS and laser scanning can also be combined on the same project; see our comparison of the 4 technologies for the detail.
How much does 3D site monitoring cost?
There is no single rate. The cost depends on three variables.
The size of the captured area, the larger it is, the more time the capture and processing take.
The frequency of visits, monthly, fortnightly, event-driven.
The length of the engagement, a pilot project over two visits is positioned at standard cost, a subscription over six months or more allows the cost per visit to be optimised.
Travel costs are calculated transparently (distance, travel time beyond the free radius, accommodation if an overnight stay is needed), billed at actual cost.
For a site in the Lausanne-Geneva-Fribourg area, the envelope of monthly monitoring is generally competitive against the cumulative cost of the physical visits avoided. See our three engagement packages to understand the structure.
How to launch a pilot on your site
Three steps to validate the value on your project, with no long-term commitment.
Step 1, identify the phase to document
Choose a phase with visible stakes (a major pour, a batch delivery, a transition between structural works and fit-out). It is on this kind of moment that the value of 3D appears fastest.
Step 2, pilot capture (1 visit)
A single capture, delivered within 48 hours. The model is shared with the project owner, architect, and subcontractors concerned. We observe what happens in the meeting, what it changes for reading the file, who takes it up most naturally.
Step 3, client feedback and structuring the subscription
On the basis of the pilot, we define together the optimal frequency, the scope to cover, the stakeholders to include, the length of the engagement. The subscription structure is adapted to the real site, not the other way round.
In summary
Photorealistic 3D site monitoring solves three persistent frictions in the sector: dispersion of documentation, multiplication of travel, fragility of proof in the event of a dispute. 3DGS technology makes this practice economically viable for the first time, with deliveries within 48 hours and viewing from a simple web link.
For a site in the region, it is an approach that few players offer yet. It is an interesting early-adoption window for project owners who want to professionalise their documentation, and for project managers who want to optimise their remote coordination.
To go further, see our Construction sector page, our site projects, or talk directly about your project via a meeting.
Frequently asked questions
How long does a capture on a construction site take?
From twenty minutes for a limited area (a floor, a shaft, a technical room) to half a day for a large complete site. The capture is non-intrusive, teams can keep working. The specialised camera we use moves in continuous motion, with no tripod to reposition every two metres.
Do the works have to stop during the capture?
No. The capture is designed to be carried out alongside site activity. Workers can be present, machines running. An on-site coordinator is useful to optimise the route, but not essential. For safety reasons, standard helmet, footwear and PPE are worn.
What frequency do you recommend for a 6-month site?
For a 6-month structural-works site, a monthly capture is a good starting point. For a fit-out site where changes are faster, a fortnightly one can be justified. On critical phases (slab pours, closing of technical ducts, installation of partitions), an occasional event-driven capture complements the regular rhythm.
How do you share the 3D model with the project owner and subcontractors?
Each delivered capture is accessible via a web link, with no app or installation. The project owner, the architect, the subcontractors open the link on their computer, tablet or phone, and navigate freely. Permissions can be restricted by password or expire after a given date.
Can you compare two 3D captures of the same site at two different dates?
Yes. It is even one of the main values of recurring 3D monitoring. Successive models are aligned to the same spatial reference, and you can switch between two dates in the same interface. It is objective proof of progress, probative in the event of a dispute over timelines or works.
Does 3D Gaussian Splatting replace a laser scan for technical drawings?
No. 3DGS produces a navigable photorealistic experience, ideal for communication, documentation and visual monitoring. For millimetre metric surveys intended for an architect or engineering firm, a point-cloud laser scanner remains the reference. The two can be combined on the same site: laser scanning for the drawings, 3DGS for monitoring and communication.
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