BIM Modelling

3D laser scanning of existing structures to BIM models in a wide range of formats including Revit & PDMS.

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Airborne LiDAR

We can provide or source lidar surveys for you based on an independent appraisal of your requirements. We also provide independent quality control, confirming the accuracy of LiDAR data sets.

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Based in England we have expanded to work throughout the world in over 50 countries.

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What We Do?

We carry out ground based, aerial and mobile laser scanning surveys worldwide. We can process scan data to produce a variety of digital products, including: BIM models using Revit, contour models, topographic feature extraction, volumetric analysis & more.

service 1

We use the latest tech

From terrestrial and airborne laser scanners to UAV drones, we use the latest and most efficient technology.

service 2

We work in all environments

From the deserts of Algeria and Oman to snow covered Greenland, we can survey in all conditions.

service 3

We deliver high quality

DTM models, contours & difference maps, Merrett Survey have provided quality products to clients for over 25 years.

Application Areas

There are many applications for terrestrial laser scanning. Some of which include:

marine surveys | oil and gas rigs | refineries | process plant | building elevations | slope stability monitoring | structures - bridges, dams etc... | mines and quarries | highway surveys | powerlines | coastal monitoring | ecological surveys | BIM | storage tanks

project 1


We can provide as-built BIM models in Revit format or as PDMS models if preferred. By creating a complete 3D model of a building, it is possible to create plans of Pipes, Vessels, Steel or a combination of any elements existing within the model. These elements can be updated to reflect changes or provide costings for proposed developments. Automatic parts lists can also be generated from the 3D Model and isometrics can be automatically generated and will update based on any changes made to the 3D model.

Our professional surveyors will laser scan your site, capturing a three dimensional 'point cloud' data set that can then be modelled and supplied in all major 3D formats. What sets a BIM model apart from just a 'dumb' 3D model of the data is that a Revit model is a Parametric Building Model, this means that changes to parameters drive the whole building model and associated documentation, not just individual components. For example, moving a wall would update the neighboring walls, floors, and roofs, correct the placement and values of dimensions and notes, adjust the floor areas reported in schedules, redraw section views, etc., so that the model would remain connected and all documentation would be coordinated.

Storage Tanks

The video (below) show a laser scan survey of a storage tank with visible shell deformation. We are able to accurately report and monitor the out of roundness of the storage tank.

By unfurling the tank shell, we can create difference images and contours to show areas of deformation. Dents are coloured blue and bulges are coloured red. Areas where the there is no deformation are coloured green.

Tank settlement can cause various changes to the shape of the bottom shell and can tilt the tank in certain circumstances. Our strapping tables not only incorporate accurate circumference and height measurements but also all internal deadwood.

Complete data capture: The laser scanner collects thousands of survey points on every surface. We also capture the storage tank surroundings allowing us to look at bund capacity and carry out spill analysis. We can survey inside and outside of storage tanks, as well as above ground and buried tanks.

Rapid: Laser scanning captures millions of points in a matter of minutes.

Accurate: The tank floor and tank shell can be accurately modelled to within +/-2mm . Deadwood assets can also be modelled. Critical features such as the strike point/plate and roof mounted gauge points, valves and sensors can be accurately derived from the scan data. Our bespoke software, developed specifically for creating tank volume tables, facilitates the creation highly accurate strapping tables. For high value products, it pays to have accurate volumes.

Merrett Survey Limited - Airborne LiDAR

Cliff Monitoring

Our experience with mapping coastal areas includes combining terrestrial laser scan data with airborne LiDAR to map a large coastal area at Lyme Regis. Deliverables included highly accurate volume computations. Beach profiles, contour maps and topographic details. Additional promotional products included animation flythroughs and LiDAR pointcloud.

We have also laser scanned failing cliffs and rockfalls, laser scanning provides a fast and safe method by which the rock face can be measured. Block sizes can be established and cross sections and contour models can be produced for use in rock fall modelling applications. Complex meshing allows for fracture mapping and fracture orientation to be established. The image (right) shows a laser scan of a cliff face with previous cross section lines merged in with the point cloud. The cliff face was meshed and then the site revisited following a rock fall. By comparing the two meshes, the volume of material that had been eroded was calculated.

The white lines show cross sections recorded years before, now superimposed on the 'point cloud' to show erosion over time. Laser scanning can reveal source zones from previous rockfall, and potential falling blocks can also be located within the scan data. This technology can prevent the need for dangerous manual surveying, which can be time consuming and dangerous.

Laser scanning provides data to study a range of parameters including discontinuty data such as persistence, dilation & roughness; and estimates of the dip and dip direction of discontinuities in the rock face. Analysis includes block size measurement and cross sections, data can be imported to rockfall modelling applications.

Merrett Survey Limited - Terrestrial Laser Scanning Heritage

Highway & rail surveys

Laser scanners are 'non-contact' instruments and are therefore ideal for scanning highways as this reduces the need for traffic management. The laser scanner creates a very large, accurate and detailed 'point cloud' that can be digitised in the office into 3D AutoCAD and MX models. The rapid data collection using laser sanning means that we can survey large areas in less time and with greater detail than by just using conventional survey techniques.

The completeness of the data capture also reduces the need for a site revisit. We have over twenty five years of experience in producing highway surveys and often use multiple techniques including airborne laser scanning and photogrammetry to complement total station or terrestrial laser scan data captured on the ground.

We provide topographical surveys for a wide variety of clients anywhere in the world. Recent projecs have included road surveys, railway surveys, airport surveys, coastal monitoring, boundary surveys and ground control for airborne LiDAR projects. Our extensive experience in providing high precision, large (and small) scale projects within a wide range of environments ensures that our work is always of high quality and specifically tailored to our clients needs.

When required we also produce cross-sections, elevations, area and volume calculations. Interior and exterior measured building surveys are also catered for. Our in-house software is specially designed for efficient processing and display of survey data, which can be provided in industry standard formats such as Autocad DXF and DWG as well as MX format. In addition, GIS data can be provided and presented via Arcview where data is collected that contains multiple attributes.

Merrett Survey Limited - Terrestrial Laser Scanning Heritage

Engineering Verification

Merrett Survey Ltd was commissioned to carry out a terrestrial laser scan survey of the supports for an atrium roof in Kuwait.

The purpose of the scanning was to survey the roof support upstands and truss positions. These were then compared to the design drawing to ensure that the roof would fit when installed.

We have recently carried out terrestrial laser scanning of a power station which was needed to determine how to install new equipment ensuring clash avoidance. A 3D model of the power station was created from the scan data and delivered to engineering firms who carried out the FEED (Front End Engineering and Design) study. We can scan your plant or factory to ensure that retrofit design projects are carried out efficiently by reducing clashes and rework.


Merrett Survey have surveyed numerous historic structures, the image shows an historic church in Lytchett Matravers. We have also scanned martello towers, Mont Orguiel Castle and its historic walls and other historic structures such as Elizabeth Breakwater in Jersey.

The benefits provided by laser scanning historic structures are significant when considering large buildings and when recording detail at height is important, such as cathedrals, tall facades and historic civil engineering structures. We do not usually require special access at height in order to record dimensional details, so long as we have line of sight to the structural detail that needs to be recorded. The precise shape of a historic structure, from bulges in a wall or the irregular spacing of timbers across a ceiling can all be measured from ground level at millimetric accuracy.

Merrett Survey Limited - Airborne LiDAR surveys

Hull modelling

By laser scanning ships hulls and decks, we can rapidly survey and deliver 2D line drawings or a complete 3D model of your vessel.

Scanning can be beneficial for a wide variety of applications as it allows us to deliver "as built drawings and 3D models". This can be useful for restoration projects, new construction, reverse engineering, hull fairing or modification projects. Some work such as scanning an engine room, superstructure detail or compartments can be carried out at sea.

Laser scanning is fast, accurate and non-intrusive, it produces very accurate data of a ships actual dimensions. Our clients have requested laser scanning and GPS surveys to determine a vessel's centreline and to calibrate it's on-board gyro. We also determined a means of calculating the heading for a recently installed ROV on a cable laying ship.

Merrett Survey Limited - Cliff Monitoring

Corridor mapping projects

We have extensive experience of using terrestrial and airborne lidar as well as photogrammetric UAV technologies to provide solutions to the powerline industry (and in fact any corridor mapping project).

Applications of the technology include:

  • Surveying of cateneries for soft (vegetation) and hard (buildings etc) clearance (vegetation management) and infringement surveys.
  • Danger tree analysis.
  • Thermal uprating of transmission lines.
  • Re-engineering - creating engineering drawings of existing towers, where plans have been lost.
  • Tower verticality and deformation reporting.
  • Conductor and/or insulator replacement.
  • Asset management - for GIS input.
  • 3D modelling of the towers and catenaries and all surrounding environments. Ideal for visualisation and presentation to the public or clients.
  • Topographic mapping of the pipeline corridor - for new build and re-alignments.
  • Sub- stations for downlead infringements, safety planning of clearances between plant.
  • Data loads directly in to PLS-CADD - and is applicable to transmission and distribution powerline networks.
  • Emergency access planning.
Merrett Survey Limited - Bathymetric Surveys


The image shows a 22-span Grade II listed structure that was originally constructed in 1860. We laser scanned the existing historic timber bridge and provided 2-D sections and a complete 3-D model of the bridge. The data was also used by engineers who were building the new bridge as well as providing an historic record of the structure.

Laser scanning of structures such as bridges, building facades, complex plant, towers etc.. enables us to create highly detailed 2D drawings or 3D models to a high accuracy.

The benefits provided by laser scanning historic structures are significant when considering large buildings and when recording detail at height is important, such as cathedrals, tall facades and historic civil engineering structures. We do not usually require special access at height in order to record dimensional details, so long as we have line of sight to the structural detail that needs to be recorded.

  • project 1

    BIM - Building Information Modeling

    From scan to BIM

  • project 2

    Storage Tanks

    Deformation Monitoring

  • project 3

    Coastal mapping

    Monitor cliff recession & beach volumes

  • project 4

    Roads & railway

    Fast, accurate & complete

  • project 5


    As-built verification

  • project 6


    Surveying historic Structures

  • project 7

    Hull Modelling

    Complex modelling of ships hulls

  • project 8

    Corridor Surveys

    Powerlines, pipelines etc...

  • project 9

    Bridges, dams & more...

    Surveying structures

About Us is a specialised part of Merrett Survey Limited's worldwide survey services. The company started trading in 1982, so in August 2012 Merrett Survey celebrated 30 years of topographical survey business. Based in the South West of England we have expanded to work throughout the world in over 50 countries including Australia, New Zealand, Algeria, France, Guinea, Bermuda, Philippines and the USA to name but a few. 

Merrett Survey was one of the first commercial organisations to invest in GPS technology so we have built up a mass of experience and knowledge. More recently we have been applying the latest surveying technologies including airborne and land based laser scanning ( LIDAR ).

It is the aim of Merrett Survey to meet the needs of our clients by providing a high quality and cost effective service. We will advise and put forward innovative ideas and new technology to benefit all parties by working in Partnership.

Merretts put forward innovative ideas and use new technology. We offer a wide range of survey services.

Our Clients

Our client list includes:-
    World Bank / Asian Development Bank
Environment Agency (UK)
Ordnance Survey (UK's National Mapping Agency)
IGN ( France's National Mapping Agency )
DPWH (Department of Public Works and Highways, Philippines)
UN (United Nations)

""Their deep understanding of GPS & rigid quality controls has particularly impressed us""

  GE Oil & Gas Client

""Merretts have shown themselves to be technically very capable, providing a positive professional approach""

  Ordnance Survey Client

"Merretts provided an excellent service when called upon. They were responsive, helpful, innovative and effective and worked well as part of the overall team delivering emergency response to the South West of England."

 The Environment Agency Client

Contact Us

3, Merlin Business Park, Fairoak Close,
Exeter Airport, EX5 2UL, UK

For UK and 'rest of the world' use-
Telephone    +44 (0) 1392 362161
Fax    +44 (0) 1392 362289

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3, Merlin Business Park, Fairoak Close, Exeter Airport, EX5 2UL, UK

+44 (0) 1392 362161

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