Delivering on all of the D’s

David Mitchell advances discussions on the importance of integrating 4D and 5D information within the individual models to create richer federated BIM that can deliver significant value at all levels of development.

Designers have learnt a lot about the challenges for BIM implementation and how to fine-tune processes and coordinate workflows between different disciplines. To date, a lot of the focus on BIM implementation, however, has been about design practitioners learning how parametric modeling can work for them and how to coordinate their workflows with other designers.

While this has been extremely encouraging for 3D, very little open discussion has happened in the fields of 4D – linking time; and 5D – linking costs.

Often 4D and 5D are reduced to the simple words ôSchedulingö and ôQuantity Take Offö, which dramatically understates the exercise. If it’s just the calculation of a schedule and quantities then we won’t know the total time and cost of the project until the models are complete. Additionally, the process is not transparent because the programmer and estimator are not at the same table as the designers and owner.

An alternative and better approach available to project teams now is for the 4D Programmer and 5D QS to pull information from the model and push back accurate data at the right time for the team to receive it. This means that:

  • the efficiency of the design is tested at an early stage when the models aren’t complete and when there is the biggest opportunity to influence time and cost;
  • an integrated programme and estimate is created that can be rerun endlessly, over and over giving instant cost and time feedback to the project team throughout all levels of development.

For BIM to be truly successful it needs to deliver on all of the D’s. The result is a better project because money and effort is targeted at the most important features and work fronts. This is done in a transparent way that builds trust amongst all project partners.

How do you integrate Time and Cost?

The answer is in how the technology is used rather than the software itself because out of the box it will do very little.

Mitchell Brandtman has invested and made significant in-roads in developing the technology to:

  • construct estimate templates and recipes that contain links between the model, the estimate calculation sheets and our rate library.
  • develop rate libraries for use in concept and detailed design.
  • improve skills to allow estimates to be calculated and recalculated easily and quickly every time the model information is revised.

Through the use of the technology, we can now see a figure or an estimate, and then flick back to the costing. The power of developing the technology in this way coupled with the skills of the 4D programmer and 5DQS is that we can visualise the programme and costs in the same way we are able to visualise design.

Early lessons learned in integrating 4D and 5D

Virtual Design and Construction (VDC) refers to prototyping construction û making construction more efficient. Construction currently suffers because it is not efficient.

Mitchell Brandtman, in conjunction with engineers, ADG, has developed a workflow for 4D and 5D planning and a contract framework to apply VDC to construction projects. Our work in this area and application to real projects contributes to advancing discussions on these issues with the view to developing a cross industry process which can be implemented into BIM execution plans.

As a collaborative team, we looked at the federated BIM and combined the different disciplines and then more importantly put the detail of the construction within the individual models.

What’s easy to do is to link a 3D model to a 4D timeframe. This technique is often used for enhancing tenders but then the visualisation is forgotten. We have developed a tool that can be updated as programmes change and the model changes.

It is also easy to link 5D information to a 3D model.

What’s difficult is getting 4D and 5D to talk to each other as they have a different make up and the processes are not the same.

By way of example, estimating a concrete structure might need 5 or 6 different rates to build up that item. In contrast, programming often requires just one duration ôform, reinforce and pourö. There is a lot of work in being able to make these different pieces of information fit together easily. But putting the time into this can be very beneficial to all project members.

Our project collaborations with ADG have resulted in delivering a updatable VDC û as the model changes the visualization changes; as the programme changes the costs change. It is fully interactive.

Through the application of the technological enhancements for recent projects we have been able to visualize how time and cost relate to each other. At the early stages of development we can easily pull information from the model and push back additional information. At later stages the type of design is more critically focused on prototyping the construction.

At Level of Development (LOD) 300 we can now integrate 4D and 5D so that we can see the money calculating as the time line progresses and visualise the programme, cost and virtual construction. More importantly we can work with the builder to revise materials, labour and other parameters and be able to fully understand the time and cost implications of unlimited alternatives. We are now also able to provide tools for builders and subcontractors to forecast their costs to complete, calculate progress payments and variations using actual cost rates. This means that we can roll the time line forward or backward and know exactly how much money would be spent within any given time.

As we progress design and build simulation toward LOD 400 we can see how the actual construction can take shape. At LOD 400 VDC can be used as a tool to explain to subcontractors and others involved in the project, exactly how it will be built. We can see all of the construction equipment, materials handling, and how the sequencing works. We are even able to prototype and visualise how and where prefabricated reinforcement is going to done. We can see the hit and miss excavation being completed, the piles being placed in the foundations, cranes being erected and how they move around, the slabs coming up and the pour sequence across the slab. We can see the temporary structures like scaffolding and safety equipment.

The difference with Mitchell Brandtman and ADG’s collaborative workflow is that the VDC is not discarded after tender. The VDC is continually updated and can be used as a management tool during construction because the dynamic links between 3D, 4D and 5D mean that the VDC is kept current easily and the critical path is maintained. Our objective is to practice the construction so that when we arrive on site it is operating almost like a factory and the critical activities are very well planned and properly thought through.

Include all the D’s in the team

The power of VDC is only just being understood now. Whilst often virtual design animation is used at tender time as a sales tool, the investment in developing it to integrate 4D and 5D brings about the real value when this is linked to a model that is updated. When our programme is updating, our cash flow is updating and we can see how these different construction sequences deliver a far more efficient construction process.

The 4D Programmer and 5D QS have developed new specialist skills that complement the traditional planning techniques. Now instead of spending 90% of our time calculating, we spend the majority of our time generating savings and efficiencies that produce better projects.

4D and 5D BIM are here, the technology is reliable and can be learnt quite easily but on its own it will not generate the certainty that is desired. This requires the wisdom and intelligence of experienced 4D Programmers and 5D Quantity Surveyors being included in the project team at all levels of development. It’s critical to collaborate and work with people who know what they are doing and how to leverage the technology to get the best results for the project.

For more information please feel free to email me director contact me at Mitchell Brandtman, 61 7 3327 5000,