How Accurate Is LiDAR Scanning? What 1–2% Means for Your CAD/BIM Files
One question we hear all the time is, “How accurate is a phone scan, really?”
It’s a fair question. We’re diving in on what you can expect for accuracy in a Scan to CAD workflow, as well as how to potentially increase that accuracy even further.
Twindo Scan to CAD Accuracy
When following Twindo’s scanning best practices with a LiDAR-enabled iPhone or iPad, most measurements in your CAD file will be within 1–2% of what you’d verify manually with a tape measure, laser distance meter, or existing blueprint.
To put that in concrete terms: on a 20-foot wall, 1% is about 2.4 inches. On a 10-foot wall, it’s closer to 1.2 inches. For most renovation, design, documentation, and space planning workflows, that’s well within the tolerance needed to work effectively.
Customers who’ve compared it against their own measurements tend to agree.
“The drawings are accurate — we’ve tested them against our own measurements,” says Ryan Moss of Jeff Adams Design.
What Affects LiDAR-Based Scan Accuracy
The 1–2% figure is dependent on scans being captured correctly. A few things can push measurements outside that range.
Scanning technique matters most. Moving through a space without using the recommended “fence painting” pattern, poor calibration, or limited coverage can all introduce errors. Twindo recommends scanning a few rooms at home before taking the app to a job site.
Some environments are harder to scan. Completely empty rooms with bare walls give the sensor and our scanning algorithms less to track against. Spaces with large mirrors or highly reflective surfaces can produce wider variances. Very small dimensions — anything under a foot — may also see slightly higher percentage error, since even a 1/16″ difference can exceed 2% at that scale.
Your iPhone or iPad’s LiDAR sensor sees what your eyes see, so there are some things Twindo can’t observe directly. Wall thickness, floor depth, and ceiling thickness are inferred from scan data and construction standards rather than directly measured. Obstructed surfaces (a curtained window, for example) may also affect placement accuracy for that specific element.
Is Scan to CAD Accurate Enough?
For most professionals working in existing spaces, 1–2% accuracy for as-built models and drawings is more than sufficient. Permit drawings, furniture layouts, space planning, FF&E documentation, renovation bidding, and commercial as-built workflows all fall comfortably within this tolerance across everything from kitchen remodels to complex historic properties.
As Steven Shields of Shields Residential puts it: “It’s more accurate than any takeoffs we’ve ever done.”
How to Improve Accuracy with LiDAR-Based Scanning
A few things that reliably improve your results:
- Follow the scanning best practices since technique is the biggest variable
- For long open spans with few surfaces, include at least one reference measurement for that dimension with your Twindo order
- For critical dimensions that need to be exact, submit reference measurements with your order
Get Accurate As-Builts from Your Scans
For most workflows, a well-captured Twindo scan delivers an as-built accurate enough to skip the tape measure, skip the return trip, and get straight to design.
Ready to see for yourself? Try Twindo today.