Anyone who works on renovations or existing buildings knows how much time can disappear into site measures.

You measure the rooms, photograph everything you think you will need, sketch odd corners and try to record enough information to rebuild the existing property back at the office.

Then, a week later, you need one dimension you did not take.

This is where 3D laser scanning can change the way existing buildings are documented.

Rather than recording individual measurements, a 3D scan captures the visible building as a detailed point cloud. Your design team can then use that digital record to measure, model and refer back to the property throughout the project.

For architects and building designers in particular, it can significantly reduce the time spent documenting existing conditions.

What Does a 3D Scan Actually Capture?

A 3D scanner records millions of measured points across the visible surfaces of a building.

For a house, this can include:

• Walls, doors and windows
• Floor and ceiling levels
• Stairs and internal openings
• Roof forms, eaves and external walls
• Decks and verandahs
• Columns and visible structural elements
• Joinery and fixtures
• Retaining walls and surrounding structures
• Irregular walls, level changes and unusual building geometry

The result is a measurable 3D record of what was on site at the time of scanning.

It is particularly useful for older houses and renovation projects where the existing building may not match old plans, walls may not be square and small differences can affect the proposed design.

Why Architects and Building Designers Use Point Clouds

For architects and building designers, the main value is not simply accuracy. It is having the existing building available digitally after leaving the site.

Rather than working entirely from handwritten dimensions and photographs, you can return to the point cloud throughout the design process.

Need to check the height of a window? Measure it.

Unsure where a wall lines up between floors? Review the scan.

Need another section through an unusual part of the house? The information may already be there.

This is particularly useful for:

• Renovations and extensions
• House raises and build-unders
• Existing building documentation
• Character and heritage homes
• Complex roof forms
• Split-level homes
• Commercial alterations and fitouts

It does not remove the need for the designer to understand the property, but it gives you a far better existing-condition reference to work from.

Using 3D Scans in Revit and Archicad

Point clouds can fit directly into common architectural modelling workflows.

For Revit users, we can provide RCP point cloud files that can be linked into the project and used as a reference when modelling the existing building.

This allows designers to work through floor plans, elevations and sections while referring directly to captured building geometry.

Archicad users can also work with point cloud data, with suitable file formats available depending on the required workflow.

The aim is not to automatically turn the house into a finished BIM model. The point cloud gives your team an accurate spatial reference from which you can build the model you actually need.

For designers who are new to point clouds, we can also provide a free online or in-house Revit walkthrough with one of our licensed building designers.

What About Interior Designers?

Internal 3D scanning is also useful where the project has little or nothing to do with the external property.

For an interior designer working on a renovation or fitout, a scan can record room dimensions, ceiling heights, windows, doors, bulkheads, floor level changes, existing joinery and other visible features.

For example, an interior designer working on a major kitchen and living renovation could use the scan to check existing openings, ceiling geometry and adjoining spaces without arranging another site measure.

For a commercial fitout, it can provide a digital reference of the tenancy before detailed design begins.

This becomes more valuable as the building gets more complicated.

How Can Engineers Use 3D Scanning?

Engineers can use point clouds to review visible existing conditions and geometry without relying solely on photos and isolated site measurements.

Depending on the project, this may assist with:

• Structural alterations
• Existing building assessments
• Measuring visible beams, columns and openings
• Checking clearances and offsets
• Retrofit projects
• Coordination with architectural models
• Existing-condition and as-built documentation

For example, if an engineer is designing new structural work around an existing house, the scan can provide useful spatial information about the relationship between visible structural elements and the proposed works.

A scan only records what can be seen, so it does not replace investigations into concealed structures or services.

What About Builders?

Builders can also get value from having a digital record of the existing building, particularly on complicated renovation projects.

A builder may use the scan to:

• Review dimensions during estimating
• Understand unusual existing geometry
• Check an area without another site visit
• Coordinate proposed work with existing construction
• Discuss site conditions with the designer or engineer
• Record existing conditions before construction

For renovation projects involving several consultants, having everyone refer to the same captured building can also reduce confusion about existing conditions.

Internal and External Scanning in One Visit

For a full-house scan, internal and external areas can generally be captured during the same site visit where access allows.

This helps connect what is happening inside the house with the external building form.

For an extension, for example, the designer may need to understand the internal floor level, external wall position, roof geometry, eaves, windows and surrounding site at the same time.

Capturing these areas together gives the design team a much more useful existing-condition record.

A Free Detail & Contour Survey With Full-House 3D Scans

A point cloud is excellent for understanding the existing building, but designers often need proper survey information about the surrounding site as well.

For this reason, Survey My Block includes a free Detail & Contour Survey with every full-house 3D scan.

This provides the project team with surveyed site information such as existing levels, contours and visible site features alongside the internal and external 3D scan.

For a renovation or extension, this means the architect or designer can receive both the building information and the wider site information from the same team.

It can also avoid organising a separate Detail & Contour Survey later when levels and site information become necessary for the design or approval process.

3D Scanning Does Not Replace Every Type of Survey

It is also important to understand what a 3D scan does not do.

A building scan does not establish legal property boundaries.

If the proposed work is close to a boundary, you may still need an Identification Survey completed by a cadastral surveyor.

Similarly, underground services, concealed structural elements and areas the scanner cannot see require other methods of investigation.

The best approach depends on what information the project team actually needs.

The Bigger Benefit: Capture Once, Refer Back Later

The value of 3D scanning becomes clearer after the initial site visit.

Instead of trying to predict every measurement that might become important during design, you have a much broader digital record of the building available to refer back to.

For an architect or building designer completing regular renovations, that can mean fewer return visits, fewer missing dimensions and less time manually documenting existing buildings.

For interior designers, engineers and builders, it provides the same basic advantage: better access to existing-condition information when you need it.

The technology itself is interesting, but that is not really the point.

The useful part is having a detailed, measurable record of the existing building sitting beside you while you work.