What is As-Built? Current Situation Documentation.

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What is As-Built? Existing Condition Documentation

As-built is a measurement-based record of the current state of a building or facility. A project drawing shows "how it was designed"; as-built documents "how it actually is on site".

The practical answer to the question "What is as-built?": Engineering documentation of the existing condition — as a drawing, model, or point cloud.

The Difference Between As-Built and Design Model

A design model (CAD/BIM/IFC) represents what will be done. It is subject to revision; it does not have to be exactly the same as the site.

As-built represents the reality at the time of measurement. Its source is site survey or ground measurement. The delivery is locked to the geometry at that date; it is not automatically updated.

In short: Design is the "goal", as-built is the "reality". Decisions in QA/QC, renovation, and facility operation are made based on as-built.

Why is it Necessary?

Identifying the difference between design and manufacturing or assembly
Basework before renovation, reinforcement, and fit-out
Plant operation and maintenance archive
QA/QC and collision control
Safe measurement for new equipment or pipe crossings

How is an As-Built Project Produced?

Scope is clarified: facade, interior, or plant line?
Site is measured: 3D laser scanning and/or classical measurement
Data is processed: point cloud merging, linking to a coordinate system
Product is produced: 2D CAD, 3D model (Scan to BIM), or raw point cloud
Control: missing area, unit, level; deviation report if necessary
Classical surveying is also a type of as-built project. Laser scanning captures complex geometry densely and holistically; handheld LiDAR can be complementary in narrow areas.

Points to Consider

LOD and level of detail must be written in the contract. The coordinate system and epoch must be specified. "Just a nice model" is not enough; measurement accuracy and scope must be clear. The delivery format (E57, LAS/LAZ, DWG, RVT, IFC) must be locked from the start.

KG Engineering

We offer as-built scanning with Leica RTC360 for industrial plants, buildings, and restoration projects; CAD and BIM delivery is also provided. You can view examples on our pages "What is Scan to BIM?", "What is Point Cloud?", and "3D Laser Scanning - Industrial Plants"; contact us for a site visit.