Accuracy
Numbers first, then how they are reached, then what gets in the way. Read all three before relying on a scan for anything with a tolerance.
- Measurement uncertainty
- 10mm typically, camera to wall
- Floor plan distance
- 0.5% or better
- Square footage
- 1% or better
- Standard
- ANSI Z765-2021 residential measurement
- Range
- 40m per scan position
- Exports
- DWG RVT SVG PDF ESX plus 360 imagery
How the numbers are reached
The camera is the iGUIDE PLANIX R1, a time of flight LiDAR sensor paired with a 360 camera. At each scan position it records a point cloud out to about 40 meters and a full panorama. The 10mm figure is the manufacturer's stated typical measurement uncertainty from the camera to a wall surface at normal indoor ranges.
Individual positions are registered into a single model. Floor plans are drafted from that model and checked against the point cloud, and every plan is measured to ANSI Z765-2021. The 0.5% and 1% figures are the tolerances the drafted plan and the reported square footage are held to against the registered model.
Accuracy on a plan is a distance figure, not a point figure. A wall drawn 0.5% off over a 20 foot span is off by a little over an inch. Over a 4 foot span it is a quarter inch. Plan your tolerances around spans, not around the headline number.
Glass
The beam passes through. Captured from adjacent positions and checked by hand.
Mirror
The beam reflects, and the scanner reads a room that is not there. Removed in processing.
Occlusion
A packed closet hides the wall behind it. More positions help, an empty room helps more.
What limits it
Glass and mirrors. LiDAR passes through glass and bounces off mirrors. Curtain wall, large mirrored walls, and glass partitions are captured from adjacent positions and checked by hand. Exterior elevations of heavily glazed facades need a conversation before booking.
Dark, wet, or very glossy surfaces. Black lacquer, wet tile, and polished stone return weaker signal. Geometry is still captured, sometimes with more noise, and is verified during drafting.
Occlusion. The scanner records what it can see. Full closets, packed mechanical rooms, and furniture pushed against walls hide wall faces. More scan positions help. Empty rooms help more.
Exterior conditions. Tree cover, tight side yards, and adjacent buildings can block a clean facade capture. When an elevation cannot be drafted to standard from the first visit, a second short visit is made and included.
What it does not measure. Anything behind a surface. Anything outside the building envelope beyond grade at the facade. The scan is not a land survey and is not offered as one.
Verification
If you want to check the scan against your own measurement, do. Pick a few long clear spans, measure them with a laser distance meter, and compare to the walkthrough's ruler tool. On a clean interior the difference should sit inside the stated tolerances. If it does not, say so and the model gets rechecked.