BIM: Live Q&A

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BIM: Live Q&A

Thank-you to everyone who took part in our Live BIM Q&A, this is now closed but if you would like to hear more, or are interested in finding out information on another topic, please get in touch at

Our panel is made up of Adrian Speller, Director of Sustainability and Ashley Poole-Graham, BIM Manager at Speller Metcalfe.


Have you made use of 3D laser surveys of existing buildings? How has the process of converting these into a useable BIM/ Revit model been? 

Robert Lewin-Jones, Jacobs UK 

AS: We have looked into 3D laser surveys of buildings, but have not had the opportunity to utilise the technology on a live project as yet.

From the work that we have done, converting into a BIM model is relatively straightforward, however, there is a large amount of data in the laser survey, so good processing power is a must!  Additionally, a laser survey provides an ‘opaque’ picture of an existing structure.  Although geometry between surfaces is extremely accurate, the laser survey will not pick up what is hidden underneath the surface.  Additional detail can be added to the model (e.g. MEP services), but this could be based on a ‘best guess’ rather than 100% accurate representation.

Still, we believe that the potential benefits that an accurate 3D model of an existing building can bring to a design development and costing process are large.

APG: We haven’t personally made use of it, but have seen some excellent examples of models that have been generated from such surveys. I understand the laser points generate the surface, which when imported into a BIM compliant programme appears as millions of dots rather than editable surfaces, it depends on the surveyor you use as to what deliverable they will provide you with?

We have used 3D point cloud survey for a number of topographical surveys, where we were provided with the survey as 3D dwg, we then used Civils 3D to convert this into a topographical surface.


What does BIM maturity level 3 look like to you ?…and how do we incentivise FMs and Asset managers to take part in the design process?

Owen Cockle, Pick Everard

APG: As yet we have not experience a project to BIM Maturity level 3, though it is an aspiration for the future. BIM level 3 is real-time collaboration with web enabled services, so the entire project team can simultaneously work on a single model source. This isn’t a reality at present for two reasons; limitations of IT infrastructure, and lack of knowledge and understanding from project teams. Project teams need to become proficient at BIM Level 2 first, and become familiar with a more collaborative approach to working, and sharing information regularly using a web-based service.

AS: I do not believe that BIM Level 3 is an impossibility, but as Ash mentions, projects have to get Level 2 right first.  In particular, on many projects we see at the moment, BIM is being implemented retrospectively – you might end up with a co-ordinated 3D model eventually, however, because a clear Employers Information Requirements is not being set out at tender stage,  clear BIM implementation plans are not being implemented. Mechanisms for management of information, and responsibilities for updating models are therefore ambiguous, sometimes meaning that the true efficiencies of BIM for design evolution are not capitalised on. Once everybody in the construction team has gotten used to formerly managed BIM implementation (from client, through to design team, to contractors), we should be able to collaborate effectively at BIM Level 3. Unfortunately, all of that will not get over the fact that where I am sitting now, in rural Herefordshire, a carrier pigeon is a faster method of communication than the internet.

APG: There are a multitude of benefits to FM and Asset Managers, but for them to realise the benefit of BIM post-construction requires buy-in from the client at the outset. I believe educating clients to realise the benefits of BIM for their facilities management team will not only enable BIM to be fully utilised throughout the project lifecycle but will ensure the benefits to the FM team are realised.

AS:  I agree with Ash, that a clear brief for facilities management, set out by educated clients is key.  However, the incentivisation that you mention is fundamentally tied to the long recognised disconnect between capital delivery costs, and long-term operating costs on managed construction projects.  If the client and construction team really focus on a Life Cycle Cost approach through design development, the significantly lower operating costs that a well designed low energy building can deliver should be incentive enough to engage FM & Asset Management teams.  This still relies on ensuring that there is a clear path of communication to include them as project stakeholders in the first place! BIM should provide a much better toolset for engaging with these stakeholders; accurate 3D visualisations, Life Cycle Costing Ability, and accurate 3D as built records with CoBie data are tangibly different to traditional 2D information.


We, as specialist sub-contractors are soon going to “switch off” Autocad and produce all our designs (for commercial kitchens) via Revit. However, there is a real lag between us wishing to fully embrace BIM and manufacturers producing BIM ready models. Is this the case across the wider construction industry and will SM begin to stipulate in any PQQs companies being “BIM L2” ready?

Peter Walker, Garners FSE

APG: Moving away from 2D line-based CAD is definitely the right move, however, we would suggest that ‘turning off’ 2D CAD is a bit of dramatic way to view the transition to working in a 3D environment. 2D information will still be required to facilitate installation on site, and as such we are seeing an approach where a 3D model is used to develop a design concept, with 2D plan and elevation views / drawings being incorporated within the building information model which are then used for production. There are significant time savings available with this approach, because, as any changes are made to the 3D concept design, the 2D drawings which are linked to it should update automatically.

We are seeing more and more manufacturers embracing this, particularly the larger outfits who have seen the advantages of moving their 2D CAD details to full 3D components. The NBS BIM library is slowly picking up steam as more manufacturers are coming on board, but is still a long way off being comprehensive. As demand for components/families increase there will be increasing pressure on manufacturers to produce their assemblies in a BIM compliant format, otherwise they will face the threat of losing market share. In the short term if you are unable to find the correct component from the manufacturer there are large libraries available on the web for BIM component/families/assemblies. These can be edited/manipulated to become a manufacturer specific object and you can add in specific parameter to suit your scheduling.  Whilst obviously ‘off the shelf’ 3D components are much more convenient, the ability to create bespoke items is a way round this.


Our first contact from companies like yours is when we receive a request to submit a tender accompanied by large amounts of documentation, how will this change post 2016 and what should we be doing to prepare for those changes?

Andy Moreton, Drewmore Interiors

AS: Hi Andy – Unfortunately, I do not think that we will ever get away from the large amount of information associated with building projects, however, the use of BIM should enable us to ensure that we are getting information to you that is specific to your trade, rather than a morass of information related to the project. The 3D environment should also help to ensure that you can get a good understanding of what the project involves through accurate visualisations, rather than having to traipse through a large paper trail of documents.

To prepare, you could look at downloading some freeviewer software … such as Navisworks Freedom, Solibir Model Viewer, DWG trueview/autodesk design review, so that you have the ability to open 3D models. If you’re happy with that, we would suggest looking at some quanity take off software, such as Cost X, Navisworks Takeoff, or Veco, which would enable you to quickly and accurately estimate quantities from 3D and 2D information, if information is not already presented in a BofQ. You can also use the same software for measuring works during construction.


Has Speller Metcalfe used any BIM models for BQ take-off purposes so far? What are the obstacles to this approach?

Robert Lewin-Jones, Jacobs UK 
APG: Yes we have undertaken several take-off exercises using BIM. We haven’t undertaken a full BQ using a 3D Model, partly because not all the model information is available when required. When we have used the 3D Model for a full take-off we have used it in conjunction with 2D drawings to supplement information that has not or cannot be modelled.

Where we have found it particularly useful is during the value engineering process. For example on a recent project we had several model revisions of the steel frame; using the 3D model we were able to rapidly evaluate the changes between current and previous revisions. A process that would ordinarily take hours can take minutes to generate and interpret.

If a full takeoff is to be undertaken using a 3D Model, the obstacles to this approach include:

1. The way in which it is has been modelled;

  • Everything should be modelled correctly and categorised in the same group from which it belongs. As an example we have seen concrete beams being used as trench foundation, or accurately labelling different wall types to enable separate takeoffs;
  • The way in which the building will be constructed; this may require some idea of the construction programme but rational judgement can be applied not just the quickest solution. As an example slabs divided into pours, or walls divided into story height not just attached to roof;
  • Further examples would include instances with internal walls, where the stud would continue to the underside of the slab but the plasterboard would finish at the suspended ceiling grid. It would require a greater degree of care in how elements are placed into the model.

2. Skill and confidence of the estimator in understanding where the 3D Model elements can be applied and where 2D needs to be applied. As well as their ability to critically interpret the model for errors.  

3. Types of procurement; some forms of contract really miss the opportunity to utilise the 4D & 5D aspect of BIM. We have seen Two Stage tenders and Design & Build as current forms of contract where the team can really exploit BIM.

4. Lack of education from design team and clients, they like to do things as they always have.


As we are a small sub-contractor, what would be the benefits to us?

Mike Wilkins – MW Glass 
APG: As a sub-contractor you produce manufacturing and assembly information, which you must coordinate with other sub-contractors to ensure your system is integrated. Usually 2D CAD and related disjointed processes are labour intensive where a lot of effort is spent updating and producing drawings. This process has a greater likelihood of inaccuracies and inconsistencies with other trades, with problems only being discovered when you arrive on site.

Information is entered into computer programs multiple times, each time for a distinct purpose, so information is inevitably duplicated within your company and by the project team. Efficiencies are squeezed by an inefficient process. BIM enabled tools will allow you to more efficiently produce and update your 2D information and schedules.

BIM is all about better collaboration with the project team, which enables more reliable and accurate information to be produced, thereby reducing risk, waste, cost and time.

Having the information you need means that you can more accurately price and run the job, with fewer clashes on site. Furthermore the majority of issues can be resolved in the office, where it is cheap to make changes; as opposed to turning up on site with loosely coordinated 2D information and resolving issues as they arise.

It may also place you in a more competitive position to price jobs. In the future, and as procurement routes change to enable BIM it will also support earlier sub-contractor involvement. This is not a distant future either, so the sooner you can begin amassing experience, the sooner you will begin to reap the rewards.

We have recently held a sub-contractor training day with a number of our sub-contractors and are beginning to see uptake from themselves as they realise the benefits. We will be holding a future subcontractor BIM training day in the not to do distant future, so if you are interested in learning about BIM in greater depth then let us know and we will put your name down.

AS: Mick, specifically for your trade, there should be better quality information available regarding the specification of glazing and sizing of units, both during construction, but also in As Built 3D models, holding that information thereafter.  From a practicality point of view, a 3D view helps us understand the logistical difficulties – say for example in getting a large glazed unit up onto an awkward to access roof area, we can plan routes, cranes, scaffold etc., better than we could using a 2D plan.


Will BIM enhance or inhibit the development and/or adoption of innovative construction techniques or technologies?

Ian Butler, Ian Butler Architects

APG: I can only see it as an enabler to innovation; innovation requires a change in process, and fully collaborative 3D BIM is exactly the mechanism the industry needs to innovate.

Using BIM based collaboration will allow a wider pool of knowledge and expertise to communicate and contribute to an overall design. Information will be available to the right team member at the right time, which enables more opportunities to collaborate and innovate.
As an example the architect needs to understand the implication of a design decision on thermal comfort, airflow and daylight, several design alternatives could quickly be generated in 3D, sent to the engineer and exported to an external analysis tool to understand the implication on energy/airflow/daylight etc. The design alternatives can quickly be calculated against parameters and the most desirable solution can be achieved. Or a more cost effective structural design needs to be achieved, alternatives can quickly be generated in 3D that can be tested in a structural analysis tool. 
BIM also enable greater co-ordination between design information and specialist fabrication. Complex fabrication information can be initiated by the designer and then developed with a specialist fabricator. The final production information can then easily be passed on to the installer, who can accurately position the element in the field. All the information required to complete a task is available at the right time and for the right person.
But to ensure these opportunities aren’t missed requires a rethink of the design and procurement. For example a subcontractor with specialist expertise may be hesitant to give full design advice to the team without a contract being secured so their involvement may be missed.
AS: BIM is definitely a tool for innovation, but we have to bear in mind that BIM software & the toolkit it brings can be quite technical.  To ensure that it really is capitalised on as a tool for innovation, software must be intuitive and focused on the realistic needs of the end user.  Additional, to drive innovation, BIM should be harnessed from the outset of projects, rather than retrospectively applied further down the design process.
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