The modern site survey workflow runs from a planning session to a BIM- or GIS-ready deliverable, and the tools used to do that work have changed significantly in the last few years. Today, a team with a phone, a laptop, and access to a few open-source tools can document existing conditions and hand off clean data to Revit, Civil 3D, or CloudCompare.
What a Modern Site Survey Workflow Looks Like in 2026
A complete modern site survey pipeline moves through pre-survey planning, on-site capture, real-time QC, post-capture cleanup and export, and downstream handoff to CAD or BIM tools. Mobile phone capture quickly documents as-built conditions for most LOD 200-300 work, as defined by the BIMForum LOD Specification. Control-point registration and survey-grade accuracy for LOD 400 or legal boundary work still requires a terrestrial scanner and external registration software.
Pre-Survey: Site Survey Workflow Checklist
Good capture starts before you leave the office. Rushing the planning step is where most mobile survey projects run into trouble later.
Step 1: Define the deliverable and accuracy requirement.
The accuracy you need determines the method you use. For as-built documentation, existing conditions drawings, and LOD 200-300 BIM models, mobile capture is typically sufficient. For legal boundary surveys, control-point registration, or LOD 400 structural or MEP coordination, you need a terrestrial scanner with GCP-registered control and external registration software.
The National Society of Professional Surveyors (NSPS) publishes model standards for surveying practice. For any work that will be certified or submitted as a legal survey, those standards apply, and mobile capture alone will not meet them.
Step 2: Plan your capture.
Walk the floor plan or site drawing before arriving. You’ll want to identify areas with limited sightlines (columns, alcoves, equipment rooms) that will need multiple scan positions. Note any areas with reflective surfaces, glass, or very dark materials that tend to cause gaps in LiDAR returns.
Step 3: Confirm equipment and conditions.
Equipment checklist for a mobile LiDAR capture:
- iPhone 12 Pro or later, or iPad Pro with LiDAR sensor.
- Fully charged device, plus a portable battery if the site is large.
- Polycam app installed and updated.
- Adequate lighting plan for interior spaces.
- Site access confirmed and safety requirements noted.
Step 4: Set expectations for the coordinate reference system upfront.
If the deliverable requires real-world coordinates (for GIS integration or site positioning), decide now whether you will use GCPs collected with a GPS unit or align to a known CAD coordinate system post-capture. This decision affects your export format and the external tools you will need. Polycam captures in a local coordinate frame; GCP registration happens in an external tool such as CloudCompare or QGIS after export.
On-Site Capture with Polycam: Best Tools for Fast Site Capture
Step 1: Set up the capture mode.
Open Polycam and select Space mode for interior spaces and detailed surfaces. For most site survey work, Space mode is the faster and more sound choice.
Step 2: Execute the sweep.
Move at a steady walking pace, roughly 0.5 to 1 meter per second. Faster movement degrades the quality of the capture. Keep the device facing the surfaces you want to capture rather than sweeping widely from side to side.
For interior spaces, a room-to-room approach works well. Capture each room at a time, moving the mobile device up and down to cover both the floor and ceiling.
For exterior facades, walk parallel to the building's face at a consistent standoff distance of 2 to 4 meters. Capture vertical features (window reveals, columns, downpipes) by angling the device toward them as you pass.
Step 3: Document features that matter to the deliverable.
Space mode captures what it sees. It does not interpret. If a pipe run, structural column, or floor joint matters to the deliverable, make a deliberate pass to capture it. Do not assume a general sweep will have caught it.
In Object mode, the general guidance from photogrammetry practice is 70-80% overlap between adjacent images for reliable reconstruction.
Real-Time QC: What to Check Before Leaving Site
Leaving the site before checking your capture is the most common cause of repeat visits. Take five to ten minutes before packing up.
Step 1: Review the mesh preview in Polycam.
After capture, Polycam processes a mesh preview on-device. Check it against your floor plan or site sketch:
- Are there obvious holes in areas you know you captured? If so, re-scan that area before leaving.
- Do corners register cleanly, or do walls appear doubled or blurred? Doubling usually means the device moved too fast through that area.
- Do floor and ceiling planes look flat and continuous, or are they wavy? Waviness in planar surfaces is a sign of motion artifacts and may require a re-scan.
Step 2: Check coverage against your planned capture zones.
Examine the mesh preview against your capture plan. Rooms or areas that appear thin or noisy in the preview will likely produce usable but lower-quality point cloud output. Re-scan if the area is important to the deliverable.
Step 3: Note any conditions that will require external processing.
If you have areas of known poor coverage (a glass wall, a very dark floor, a heavily shadowed alcove), note them before leaving. These will need either a re-scan or a note in the deliverable that coverage is limited in those areas. For users of Polycam, you can use walkthrough mode, which overlays images directly on the 3D surface.
Post-Capture: Cleanup and Export as Point Cloud
Step 1: Process the capture.
Processing time in Polycam scales with scan size. Larger captures can be sent to Polycam's cloud processing rather than processed on-device.
Step 2: Crop and clean the point cloud.
Use Polycam's crop tools to remove points outside your area of interest, such as the sky above an exterior scan, adjacent buildings you are not documenting, or ground plane noise below a floor slab. Removing unneeded geometry before export reduces file size.
Step 3: Export in the right format.
For AEC workflows, export as LAS or LAZ. LAS is the ASPRS standard format for LiDAR point clouds and the format that downstream tools, including CloudCompare, QGIS, Autodesk ReCap, and Civil 3D, expect. LAZ is the losslessly compressed version, typically 7-20% of the original LAS file size with no data loss.
To export from Polycam:
- Step 3a: Tap the Share / Export button.
- Step 3b: Select Point Cloud as the export type.
- Step 3c: Choose LAS or LAZ from the format dropdown.
- Step 3d: If your capture has georegistration data, or you plan to register to a known coordinate system, set the CRS before exporting.
For mesh-based deliverables (rendered images, walkthroughs, or BIM-adjacent documentation), export as OBJ, FBX, or GLB.
Registration and Alignment: Handoff to External Tools
Polycam captures in a local coordinate frame. It does not perform GCP registration or ICP alignment natively. If your deliverable requires real-world coordinates, alignment to a control network, or merging multiple scan sessions with precise overlap, that work is done in an external tool after you export the point cloud.
Step 1: Load the Polycam LAS export into CloudCompare or QGIS.
CloudCompare is a free, open-source point cloud processing tool with full LAS read and write support. It is the standard choice for manual registration and ICP-based fine alignment of point cloud data.
According to the CloudCompare documentation, the tool offers several registration methods: manual bounding-box centering, interactive point-pair picking, and automatic fine registration using the Iterative Closest Point (ICP) algorithm. The ICP tool finds the best-fit transformation between two overlapping clouds. The documentation notes that the ICP fine registration is designed for clouds that are already roughly aligned; it is not capable of coarse registration from scratch.
Step 2: Perform coarse alignment first.
Before running ICP, align the clouds using CloudCompare's point-pair picking tool (Align> Point Pairs Picking). Pick three or more corresponding points in each cloud: column corners, wall junctions, or identifiable floor features work well. CloudCompare computes the transformation and applies it to approximately align the clouds.
Step 3: Run ICP fine registration.
With the clouds roughly aligned, run Tools > Registration > Fine Registration (ICP). CloudCompare adjusts the transformation to minimize the distance between the two clouds. The result is a 4x4 rigid transformation matrix, which CloudCompare outputs to the console and applies to the cloud.
Step 4: Register for GCPs if real-world coordinates are required. (20 to 60 minutes)
If your deliverable needs real-world coordinates, you will need GCPs collected with a GPS unit or total station. From there, you will need to load into CloudCompare or QGIS and use it to georeference the Polycam export. The Polycam LAS export is the input, and the GCP registration is performed in the external tool. QGIS has LAS import support and can manage point cloud layers alongside vector GCP data.
Handoff: Which Format Goes Where
| Destination | Format | Notes |
|---|---|---|
| Revit | LAS to ReCap (RCS/RCP) | Import LAS into ReCap, link RCS/RCP into Revit. |
| AutoCAD Civil 3D | LAS to ReCap (RCS/RCP) | Civil 3D 2018+ requires ReCap conversion |
| CloudCompare | LAS or PLY | LAS for full attribute preservation; PLY for normals |
| QGIS | LAS / LAZ | Native support; strong for GIS-referenced workflows |
| BIM coordination (Navisworks) | RCS/RCP via ReCap | ReCap file reader links natively |
| General documentation | OBJ or GLB | For rendered deliverables, walkthroughs, or client-facing visuals |
When to Use Mobile vs Terrestrial Laser Scanner
Use Polycam mobile capture when:
- The deliverable is LOD 200 or LOD 300 (existing conditions documentation, space planning, preliminary BIM)
- Speed matters more than sub-millimeter accuracy.
- You need to capture a site quickly before a building is demolished or handed over.
- The budget does not support a full terrestrial scanning engagement.
- The area is too small, or access is too constrained for a tripod scanner setup.
Use a terrestrial scanner when:
- The deliverable is LOD 350 or LOD 400 (structural, MEP coordination, fabrication).
- Legal survey accuracy is required, or the work will be certified by a licensed surveyor.
- The site requires registered multi-scan point clouds with known control points.
- Accuracy tolerances are specified in millimeters rather than centimeters.
- The deliverable will feed directly into structural analysis or precise fabrication.
Polycam is a fast and accessible phone-based capture layer for documentation and as-built work up to LOD 300. It does not replace a Trimble SX12 or a Leica RTC360 for high-accuracy survey work. What it does do is make that level of documentation available to each team member with a phone, without a specialist operator or expensive equipment rental. For many site visits, that is exactly what the job calls for.
Tools like Matterport, DJI drones with Pix4D processing, and dedicated mobile mapping systems each occupy different positions in this landscape. Matterport is strong for visual walkthroughs and dollhouse views, but produces less usable raw point cloud data for CAD workflows. DJI plus Pix4D is the standard choice for large exterior site surveys and aerial mapping. Polycam sits between these: better-structured point cloud output than Matterport for downstream AEC use, and better interior capability than drone-based capture.
Site Survey Workflow Checklist
Pre-survey:
- Deliverable type and accuracy requirement confirmed.
- Capture zones are mapped against the floor plan or site drawing.
- Equipment checked and charged.
- Lighting plan for interior spaces.
- The CRS and GCP strategies determined whether real-world coordinates were needed.
On-site:
- LiDAR or photogrammetry mode is selected for the conditions.
- Steady sweep pace maintained (0.5 to 1 m/s).
- Room-to-room overlap of at least 2 to 3 meters.
- Key features captured with deliberate passes.
- Mesh preview checked before leaving the site.
- Re-scan triggered for any obvious gaps or artifacts.
Post-capture and handoff:
- Capture processed (on-device or cloud).
- Point cloud cropped to the area of interest.
- Exported as LAS or LAZ.
- Loaded into CloudCompare or QGIS for registration if needed.
- CRS set if geo-registration is required.
- Delivered in downstream format per the handoff table above.
FAQ
What does a site survey workflow checklist include? A complete site survey workflow covers three phases: pre-survey planning (deliverable type, accuracy requirements, equipment, lighting, and CRS strategy), on-site capture (sweep patterns, coverage, real-time QC), and post-capture handoff (cleanup, export format, registration if needed, and delivery). The checklist above covers all three phases.
What are the best tools for fast site capture? For interior as-built documentation and LOD 200 to 300 work, an iPhone or iPad with LiDAR and Polycam is one of the fastest options available. For large exterior sites, a DJI drone with Pix4D processing is standard. For high-accuracy multi-scan registration, terrestrial scanners from Trimble or Leica Geosystems remain the professional benchmark. The right tool depends on the accuracy requirement and the deliverable.
What are the alternatives to LiDAR scanners for site surveys? Photogrammetry (using overlapping photos to reconstruct a 3D model) is the main alternative. Tools like Pix4D, Agisoft Metashape, and Polycam's Object mode all use this approach. Photogrammetry can produce dense, colorized point clouds yet requires more controlled lighting and more processing time than LiDAR. For interior work, Matterport uses a combination of LiDAR and structured light. Each method has trade-offs in accuracy and workflow depending on site conditions.
How do I document as-built conditions swiftly? The fastest approach for most interior as-built documentation is a phone scan: capture, process, export as LAS, and load into your CAD or BIM tool the same day. For a 1,000-square-meter floor plate, a thorough sweep in Polycam typically takes 10 to 15 minutes on site, followed by 10 to 20 minutes for processing and export. Compare this to a full terrestrial scanning engagement, which may require a specialist operator, a half-day on-site, and several days of office processing.
What are the steps in a scan-to-BIM workflow? The core steps are: site capture, point cloud cleanup and export, registration and alignment if multiple scans or real-world coordinates are needed, conversion to RCS/RCP via Autodesk ReCap for Autodesk tools, linking into Revit as a reference for BIM modeling, and LOD-appropriate modeling from the point cloud reference.
Does Polycam register to ground control points? No. Polycam captures in a local coordinate frame. GCP registration, which ties a point cloud to surveyed control points with known real-world coordinates, is performed in an external tool such as CloudCompare or QGIS after exporting the Polycam LAS file. If real-world coordinates are required for your deliverable, plan for this external step before the site visit and collect GCPs with a GPS unit or total station.
How do I load a Polycam point cloud into CloudCompare? Export your Polycam capture as LAS. Open CloudCompare, go to File > Open, and select the LAS file. CloudCompare reads LAS natively. If the coordinates appear very large (from a geo-registered export), CloudCompare will prompt you to apply a global shift to bring the cloud closer to the origin for processing. From there, you can crop, clean, register with ICP, or export in any of CloudCompare's supported formats.