Recording up to 900,000 points of data per second the scanner creates a 3D point cloud with the definition of a 39 mega pixel camera, accurate to 2mm.

As-built 2D building plans, elevations, floor and reversed ceiling plans can all be created easily from the survey. Items are captured to such a level of detail that cornicing or other decorative elements can be re-cast exactly from the 3D data.

Digital have just returned from the Bladt Industries ship yard in Aalborg Denmark where we carried out an as built survey for two offshore wind farm decks. Using laser scanning we were able to capture exact 3d models of the decks. This data was used to carry out dimensions control checks ensuring that the decks would fit correctly onto corresponding towers which were being fabricated back in the UK. Laser scanning is becoming the preferred method for accurate dimensional control and as-built surveys as it captures all details down to the smallest nut and bolt. This provides a digital 3D record for QA and allows virtual inspection of the wind farm components back in the office.

Bladt industries are steel contractors specialised in manufacturing large complex steel structures supplemented with turnkey solutions and competent project management. Bladt fabricate steel structures for all sorts of purposes such as suction anchors, wind mill towers and foundations, shore-to ship installations, bridges, steel tanks, buildings, topsides and jackets.

Digital have recently carried out a 3D laser survey for the Bamburgh Research group. The BRP is a non-profit independent archaeological research project investigating Bamburgh Castle in Northumberland, one of the most important archaeological sites currently under excavation in northern England. The BRP was set up in 1996 to investigate the history of this fascinating castle and its environs from prehistory to the present day, and it aims to bring that past to life for everyone.

Over the years the Archaeologist have been working on a number of trenches.

By utilising our 3D laser scanner we were able to document trench 3 in high quality for future reference. Over the coming months we hope to also digitally capture trench 1 and the main castle keep. The 3D laser scanner creates a snap shot in time of the site and has become another essential tool available to archaeologists. We plan to return and digitally document the site in future which allows us to develop a 3D model showing the excavation changes over time.

Scanning to Meshing.

One of the main workflows we’ve been investigating at Digital is to produce high quality solid models from 3D laser scan data. Currently there are a variety of different workflows and software packages available. The main constraint is down to the high prices that many of these pieces of software cost. There are lots of different options out there and for small business’s deciding which route to invest in can be a tricky business. As well as the purchase cost there is the cost of training staff in multiple packages. The 2 big guns in meshing software packages are:

• Polyworks

• Geomagic

Both offer a large range of functionality and come from a reverse engineering and industrial background. With 64bit versions of both available they can crunch large point clouds easily. However this comes at a cost, both are serious bits of software and as such come with a heft prices tag. From a surveying perspective they also come with lots of additional options which might not ever get used, making the justification for such a large investment hard. Polyworks has some great QA options built in which can be essential if you are modelling for safety critical applications, where a paper trail in necessary. Geomagic Studio can handle very large datasets easily and has a lower learning curve with its built in wizards.

Both are fantastic bits of software but don’t expect to get much change from £10,000.

Once you’ve created your meshes these need to be cleaned, fixed and decimated to usable levels and imported into your 3D rendering software. The most popular are Maya and 3DStudio Max.

This again requires more software investment and skills. As part of our ongoing research we’ve been trialling some alternative options to these packages, reducing the number of expensive seats required.

There are cheaper meshing solutions out there that maybe more appealing to survey companies. We’ve been looking at 3D Reshaper and VRMesh and for compositing Blender an open source, cross platform suite of tools for 3D creation.

The cheapest of these two VRmesh has some nice features but struggled with any sizeable point clouds making it not very appealing for large survey datasets. 3D Reshaper on the other hand handled large point clouds very well and had surprisingly fast meshing capabilities. Although the meshes created were not as detailed as those you would expect from Geomagic they were very usable and provided some good results. Mesh cleaning and hole filling options were a bit limited and seemed a bit unstable as trying to fill a hole with an open contour crashed the software. However 3D Reshaper has some other nice options such as feature line extraction of breaking lines for land surveying and architectural purposes.

Once the meshes had been created they were exported as .obj file to blender. Blender provides many features you would expect in high end 3D packages and a wealth of online tutorials to get started. It has a basic rendering engine which provided good images and built in animation options. Another piece of open source software worth mentioning is MeshLab. Meshlab is an open source, portable, and extensible system for the processing and editing of unstructured 3D triangular meshes. Its a great free piece of software for viewing and editing meshes. All in all this workflow offers an alternative to the large vendors and with many project budgets being slashed provides a viable cost effective option for 3D modelling.

Renders:

Digital have recently returned from a week scanning Mont Orgueil castle in Jersey for Channel 4s Time Team. Always looking to be at the forefront of heritage and survey technology, Time Team approached Digital to use our 3D laser scanning services.

Over the week we scanned as much of the castle as possible, as well as being interviewed for the series. A full case study with videos and examples will be online shortly.

Digital have recently returned from a trip to Kristiansund in Norway where we carried out a 3D laser survey of the Nordica. The MS Nordica is a Finnish ice breaker, however she is a multi purpose vessel intended to operate in the offshore industry outside ice season. CTC Marine of the Trico Marine Group will be using the Vessel for cable laying and Digital were commissioned to digitally document the ship. The laser survey has many advantages as it means that all aspects of the deck have been recorded eliminating the need for costly revisits to the Vessel.
View full case study >>>

AutoCAD 2011 has introduced native point cloud support. This step shows that the market is slowly moving towards acceptance of laser scanning data. Up until now 3Rd party software has been required to pull point cloud data into AutoCAD.

Although this is a move in the right direction, initial reviews from users are reporting limited functionality. Specialist plugins such as Leica Cloudworx or Pointools Model currently allow for advanced data management, as well as tools to slice, crop, hide and managed the point cloud data once in AutoCAD. Although AutoCAD 2011 will allow users to view point cloud data it doesn’t seem to offer these more advanced options required to utilise point cloud data.
Autodesk rival Bentley Microstation have also licensed the more advanced Pointools Vortex engine for future releases of their software. Pointools is currently one of the leading engines for manipulating point cloud data. Wider acceptance is coming slowly but users are still required to jump through various different software applications to get their desired results. Hopefully standardisation for generic point cloud formats will come shortly.

The laser scan will allow us to check the accuracy against as built plans and provide an exact model for Ansons QA and documentation.

There are many different laser scanners for LiDAR surveys on the market. Currently they all have their advantages and disadvantages depending on the job at hand and the required client deliverable.

Pulse based scanners tend to be slower but have a longer range while phase based scanners are much faster but have a much shorter range. At Digital Surveys we mainly use Leica’s Scanning technology for terrestrial LiDAR projects and own a Leica Scan Station 2 which is currently 10-times faster than other pulsed scanners, and is generally regarded as the best all round scanner on the market. We also use the industry standard software Cyclone and Cloudworx. We also have experience using Trimbles GX scanner and Realworks software.

LiDAR and High Definition Surveying is quickly becoming the preferred technology for very detailed survey projects. It has been embraced by many heritage and conservation organisations who are using it to record exact replicas of historical and archaeological sites and buildings.

We are currently working with leading heritage organisations in the North East on a number of prestigious scanning projects. The main one being the scanning of Alnwick Castle home to the Duke and Duchess of Northumberland and also used in the filming of Harry Potter as Hogwarts!!

Typical deliverable from a LiDAR laser scanning project are the Raw Point Cloud data as well as high definition ortho rectified images and traditional 2D elevations, plus 3D flyby and walk through movies. From the point cloud, elements can be sliced up and meshed to create full 3D models that can be exported and worked on in packages such as Autocad, Geomagic and Rhino.

Aerial LiDAR works on the same principals however the laser is mounted on a light aircraft and the scanning is carried out from above. Aerial LiDAR is best suited for covering very large distances where accuracy isn’t as important.

If you are interested in our LiDAR and 3D laser Scanning services then please email ben.bennett@digitalsurveys.co.uk to discuss your requirements