Every renovation starts with the same question: what exactly is there now? How you answer it — hand measurement, scan-to-CAD, or scan-to-BIM — shapes design quality, coordination risk, and change-order exposure for the rest of the project. Here's how the options compare and when each one makes sense.
The Three Ways to Document Existing Conditions
1. Traditional Hand-Measured As-Builts
A person with a tape or disto measures the building and drafts plans. Adequate for a small, simple, rectangular space. The weaknesses show up fast in older Bay Area buildings: out-of-square rooms get forced square in the drawings, ceiling and floor variation disappears, and anything not measured on-site means another field trip. Errors surface during construction, priced as change orders.
2. Scan-to-CAD (2D Deliverables from a Point Cloud)
The building is laser scanned, and 2D floor plans, elevations, and sections are drafted from the point cloud. You get drawing accuracy backed by millions of measured points, plus the cloud itself as a permanent record — if a dimension question comes up in month six, the answer is in the data, not another site visit. This is the sweet spot for most residential remodels, tenant improvements, and permit packages.
3. Scan-to-BIM (3D Revit/IFC Model)
The point cloud becomes a full 3D model — walls, floors, roofs, structure, and optionally MEP — built to an agreed level of development. This is the right call when the design team works natively in Revit, when MEP coordination in tight existing spaces matters, or when the owner wants a digital twin for long-term facility management.
Quick Comparison
| Factor | Hand-Measured | Scan-to-CAD | Scan-to-BIM |
|---|---|---|---|
| Accuracy | Inches, variable | Millimeter-backed | Millimeter-backed |
| Complete record of the building | No | Yes (point cloud) | Yes (cloud + model) |
| Return site visits needed | Common | Rare | Rare |
| Relative cost | $ | $$ | $$$ |
| Best for | Small simple spaces | Remodels, TIs, permits | Revit workflows, MEP, complex buildings |
Two Details That Matter More Than the Format
Specify the Level of Development (LOD) Up Front
"A Revit model" means nothing without an LOD. LOD 200 gives generic placeholder geometry; LOD 300 gives accurate size, shape, and location suitable for design; LOD 350 adds the interfaces between systems. Modeling effort roughly doubles at each step — agree on it before anyone prices anything, and specify which elements (architecture, structure, MEP) are included.
Ask Who Controls the Scan
A model is only as good as the point cloud under it, and a point cloud is only as good as its registration and control. Surveyor-led scanning ties the data to a verified control network — and to the property boundary and site grades when the project needs them. That's the difference between a model that coordinates with civil, structural, and permit requirements and one that quietly disagrees with the site.
Not sure which deliverable your project needs? See our 3D laser scanning and as-built services — we'll recommend the lightest deliverable that actually de-risks your project.