Church As-Built Survey with 3D Laser Scanning in Vung Tau

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As-built survey of a church with 3D laser scanning for renovation and repair: Betania Bai Dau project, Vung Tau

5,000 M² · TOTAL FLOOR AREAABOUT 30 YEARS · BUILDING AGE4 METHODS · 1 COORDINATE AND HEIGHT DATUMVUNG TAU · BAI DAU

3DSCAN carried out an as-built site and architectural survey of the Daughters of Charity of Saint Vincent de Paul – Betania Bai Dau Community, 162 Tran Phu Street, Vung Tau, as the basis for planning the renovation and repair of the building. The church was built about 30 years ago as a series of stepped blocks, with a total floor area of about 5,000 m². The survey combined 3D laser scanning of existing architecture with a Leica RTC360, static GNSS observations, height transfer by levelling and UAV imagery from above, all tied to a single coordinate and height datum.

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A stepped church: the hard part is tying every level into one drawing set

At Betania Bai Dau, measuring each area was not the difficulty. Making those areas fit together was. The stepped structure creates many floor and roof levels and many transitions between blocks. If each part is surveyed in isolation, plans, elevations and sections easily drift apart when they are joined.

After many years of use, archived drawings (where they exist) do not necessarily reflect the building as it stands after repairs, alterations and later additions. The key requirement of the survey was therefore to establish a single, consistent spatial survey framework, so that the designers could fix the correct position, dimensions and height relationships of every element planned for renovation.

As-built geometry is an input to design. It does not replace a quality inspection or a structural load-capacity assessment.

A multi-block campus on sloping rock

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Front of the Betania Bai Dau Community seen from Tran Phu Street, Vung Tau — Front elevation from Tran Phu Street

Tiled rear courtyard looking out to the sea at Bai Dau — Rear courtyard facing Bai Dau beach

Multi-storey block and two pine trees in the front yard of Betania Bai Dau — Multi-storey block in the front yard

Low-rise blocks linked by covered walkways within the campus — Low-rise blocks and covered walkways

Concrete staircase connecting floor levels inside a block — Staircase linking floor levels

Natural stone retaining wall running along the foot of the Betania Bai Dau building — Stone retaining wall at the building's foot

Tall stone retaining wall at a corner of the campus, topped with netting and climbing plants — Stone retaining wall at a campus corner

Four survey methods, one shared coordinate and height datum

The data only becomes valuable when all four sources sit on the same reference system.

Schematic diagram, not to the building's scale.

In the diagram, the Leica RTC360 laser scanner records the geometry on each floor level, a levelling line runs from the control mark through the blocks to lock in the height differences, static GNSS positions the building within the campus, and the UAV captures the roofs from above. The output is a set of floor plans for each level, elevations, sections and an as-built site plan on one coordinate and height datum.

Leica RTC360 captures the architectural space in 3D

The Leica RTC360 3D laser scanner collects point cloud data from stations with suitable lines of sight. The data records surface shapes, the positions of visible building elements, interior and exterior spaces, the junctions between blocks and the changes in level. According to the Leica Geosystems datasheet, the RTC360 measures up to 2,000,000 points per second with a 3D point accuracy of 1.9 mm at 10 m, and its VIS technology supports on-site registration of scan stations. These are instrument specifications, not the project's acceptance tolerances. From the point cloud, engineers extract as-built floor plans, elevations and sections to suit the design package.

Leica RTC360 laser scanning on site

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Leica RTC360 laser scanner on an upper floor, with the hills and city of Vung Tau behind — Leica RTC360 on an upper floor

Engineer operating the Leica RTC360 scanner under a canopy between blocks — Engineer running a station under a canopy

Leica RTC360 scan station at the foot of a block, between planters — Station at the foot of a block

Leica RTC360 scan station in the garden on the high rock terrace of the campus — Station in the garden on the high rock terrace

Leica RTC360 scan station on a low-level path beside the stone retaining wall — Station on a low path beside the retaining wall

3D laser scanning of the kitchen while staff are still working — Scanning the kitchen while it is in use

Leica RTC360 scan station in the front yard in the evening — Front-yard station in the evening

Leica RTC360 scan station on the seafront pavement in the evening — Station on the seafront pavement at dusk

Static GNSS places the building in a consistent reference system

Static GNSS observations were used to build the coordinate control network that links survey data from different parts of the building. Before going into the as-built site plan, the observations must be processed, checked and tied to the common reference system.

Levelling keeps the height differences between blocks correct

On a stepped building, heights are where errors most easily creep in when data is combined. Transferring heights by levelling provides an independent check on the height differences between areas. These values are used to tie together floors, courtyards, steps and junctions, limiting discrepancies when the survey datasets are merged.

UAV adds the view of roofs and grounds

UAV imagery gives an overview from above: the site layout, the roof levels and the relationship between the building and its grounds. It is a supporting data source, familiar from UAV topographic surveying and from combining UAV data with laser scanning, and most useful on roof surfaces that are hard to see from the ground. Occluded areas still need additional checks if they fall within the design scope.

Questions in the renovation brief and the method that answers each

What the designer needs to know	Primary method	Support / notes
Shape and dimensions of visible elements; interior and exterior spaces	3D laser scanning with Leica RTC360	UAV for exterior surfaces and roofs
Position of the building within the campus	Static GNSS	UAV imagery for the overall layout
Height differences between courtyards, floors, steps and storeys	Levelling	Cross-checked against the point cloud
Roof surfaces and roof levels hard to see from the ground	UAV	Additional checks in occluded areas
Material strength, load-bearing capacity	Outside the scope of a geometric survey	Requires a separate specialist inspection

What the as-built data lets the designers do

After the fieldwork, the data from all methods is checked and organised within one consistent position and height system. Depending on the scope agreed with the design team, the survey database can support:

As-built site plan: defining the spatial relationship between the building, its grounds and related features.
Architectural drawings: floor plans for each level, elevations and sections based on the existing geometry.
Height cross-checks: clarifying the height differences between courtyards, floors, steps, roofs and the junctions between blocks.
Renovation design support: less reliance on estimated dimensions when planning layouts, repairs or changes of use.
Digital record: keeping the as-built data for reference and, when needed, developing a Scan to BIM model.

The core value of the solution lies in linking coordinates, heights and 3D geometry, not in any single instrument. It means the renovation design is based on the actual condition of the building.

Spaces to be surveyed for the renovation design

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Multi-storey block with external corridors and steel railings — Multi-storey block with external corridors

Tiled upper-floor corridor with stainless steel railing overlooking the courtyard — Upper-floor corridor and railing

Existing rooms and window openings along the corridor — Rooms along the corridor

Common room with its existing columns, beams and tiled floor — Common room

Existing kitchen with windows and a doorway to the rear area — Kitchen

Metal-roofed walkway connecting the blocks within the campus — Metal-roofed walkway between blocks

Metal roof and solar water heaters on top of a block — Metal roof and solar water heaters

Measure the existing condition correctly before intervening

The Betania Bai Dau project shows how 3DSCAN surveys complex existing buildings: combining 3D laser scanning, static GNSS, levelling and UAV into one consistent survey dataset for renovation and repair. The approach suits buildings whose architectural character needs to be preserved when interventions are planned. 3DSCAN is headquartered in Ho Chi Minh City and carries out as-built surveys for projects in many provinces across Vietnam.

The building before renovation

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Main block of the Betania Bai Dau Community seen from the courtyard — Main block from the courtyard

Front yard and multi-storey block, with seafront high-rises behind — Front yard of the main block

Corner of the front yard with stone-built planters and a row of areca palms — Yard corner with stone planters

Multi-storey block with a glazed wall section and balcony corridors — Block with a glazed wall section

Related projects and solutions by 3DSCAN

3D laser scanning of the existing building at 12 Vo Van Kiet, District 1: as-built data for an existing building in Ho Chi Minh City.
As-built laser scanning for a building renovation: applied to a repair design package.
Laser scanning for structural inspection of a 10,000 m² factory roof: roof geometry data supporting structural inspection.
3D laser scanning of St. Joseph's Cathedral, Hanoi: recording the geometry of a religious building.

Do you need an as-built survey of a church, a multi-level building or an existing structure before repair work? Contact 3DSCAN to discuss the survey scope and the data your design team needs.

Contact 3DSCAN Hotline: 0938 309 808 · Email: lienhe@3dscan.vn

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Frequently asked questions (FAQ)

Why does a church need a new as-built survey before renovation?

Because repair design must be based on actual dimensions, positions and heights. The Betania Bai Dau church has stepped architecture and about 5,000 m² of floor area, which makes linking information between storeys and blocks all the more important.

Is a UAV survey alone enough for a church as-built record?

No. A UAV helps capture roofs and the overall site from above, but it cannot fully record interior spaces or occluded areas. The project combined the Leica RTC360 with static GNSS and levelling to complete the geometric, positional and height information.

Can 3D scan data replace a structural inspection of a 30-year-old building?

No. A point cloud records visible surfaces and geometry, but it cannot determine material strength, load-bearing capacity or the condition of concealed elements. Those require a separate specialist investigation and assessment.

Does 3DSCAN survey churches in Ho Chi Minh City and other provinces?

Yes. 3DSCAN is headquartered in Ho Chi Minh City; the Betania Bai Dau church in Vung Tau is one completed project, and the company has also laser scanned St. Joseph's Cathedral in Hanoi.