Documenting Existing Conditions Without a Site Visit

Every existing-conditions model I've built remotely has come from one of three sources: point cloud scans, survey CAD files, or a combination of photos and field measurements taken by someone on-site. Each has a different reliability profile, and mixing them without knowing which parts are solid and which are estimated is where models go wrong.

Point clouds are the closest thing to being there

When a scan exists, I bring it into Autodesk Recap and model directly over it. Wall locations, floor-to-floor heights, and openings come from the scan itself, not from an assumption. This is the source I'd point to first if a firm is deciding whether to pay for a scan on a renovation project — it removes almost all of the guesswork on the shell of the building.

Survey CAD is reliable for what it covers, and nothing else

A property or topographic survey is precise for the elements it was made to capture — property lines, grades, sometimes a building footprint — but it usually stops there. It won't tell me interior partition locations, ceiling heights, or what's actually behind a wall. I use it as the geometric anchor for site context and treat everything inside the building as a separate question.

Photos and measurements work, with real limits

Dimensioned sketches and a good photo set can get a small, simple space fully modeled. Where this breaks down is anything that isn't directly visible or measured — ceiling cavities, structure inside a finished wall, a room nobody photographed. On these projects I build what the data supports and flag the rest explicitly as an assumption, rather than quietly filling the gap with a guess that looks confident on screen but isn't backed by anything.

What I won't do

I don't do the on-site capture myself — I'm in Buenos Aires, so scanning, measuring and verifying conditions in the field has to be your team or a local surveyor. And I don't present an assumption as a fact: if the data doesn't support a dimension, the model says so, so it gets verified before it drives a construction decision instead of after.

For what this looks like on a real project, see the multifamily existing-conditions case study, or the full breakdown on Existing Conditions / Scan-to-BIM.