4D Construction Group
Yeah would always recommend working with one programme so that everything stays integrated. You can make best use of whatever scheduling software you’re using to apply codes and WBS to be able to filter, summarise or present different views of that programme for any purpose.
Hi Sachin, good question. There's a long answer to this, and there are others on here that are more qualified than me to answer, but I'll outline some thoughts.
In our experience as 4D modellers, it's best to use the same schedule you'd use normally. A seperate schedule is not required and can cause problems updating and progress monitoring. The 4D model should be linked to the 'real' schedule in a way that is consistent and aligned.
It's sometimes a good idea to section off parts of the schedule / model / works for use in 4D planning workshops. This can be a temporary section that gets plugged back in later, or can remain attached to the master schedule and managed like that. This allows for testing ideas, schedule development, and collaborative planning on focussed tasks in a quick, iterative way. Others like Chris (Needham) and David-John (Gibbs) on here may provide some good views on this.
In terms of 4D model content, we always recommend representing as much as possible. As many tasks as possible, and as many logistics, access and other activities as possible. Ideally, nearly everything that is worth seeing in a schedule should be worth seeing in 4D. Of course this requires an investment in modelling time, skills, and can impact model performance without good model and file management.
It's certainly an aspiration for us to aim towards. Though there is plenty of value in starting 4D with just the basic, key activities.
"The 4D model should be linked to the 'real' schedule in a way that is consistent and aligned". This is the normal schedule, right? How is it linked to the model? How the planner is able to connect to the model?
Just the normal way of doing a schedule if that’s what you mean. Usually a schedule is high level and you can detail it down to an extent you’re comfortable with. Since a 3D model is available and you can modify the geometry (in some 4D software, I suppose) on how you will construct it, it is the same with the schedule if you’re further detailing the activities or using rules of credit. The same principle but just better visualisation with a 3D model instead of 2D drawings.
As [@James Bowles] said, it is recommended to consider details as much as possible. It is also good if the planner has some knowledge on how a model is done.
Easiest answer, yes should be. However does the programme you find yourself working with from a client or sub contractor or even your own team have enough detail to link 3D objects to?
Has the planner been lazy and written multiple events in one row? I had that with track renewal train movement programme. Text was very short and full of lots of acronyms so will write out more fully here - text would read something like, Loco 6A enters on down fast line, switching to downslow across the 1234 points, the 4321 points and reverse into sidings (duration 30mins). So breaking that down in 4D software would mean one task becomes three more child ‘4D’ activities to get the train to move like that. you would also have guess each move would take 10mone to fit in that 30m duration.
Ok so that’s a little out of the normal, but piles example is a good one. Many planners would just put piling 2 weeks duration...and sometimes a Left to Right install profile will work, but sometimes there are very specific sequences and you would need each pile to be in the programme. But you don’t always want that LOD in your master programme.
As long as your 4D activities nestle nicely inside your construction programmes happy days. But it’s a bit like the 4D model, it may be based on the BIM model but sometimes you need to simplify (too much heavy detail) or add temporary works models to that BIM model to represent sequence.
Please don’t say BIM model...!
I think there should be one programme, and the programme should be detailed enough to build to and therefore, be able to be shown using 4D. This is often one of the benefits of 4D (which is what you’re saying here also) as if there isn’t sufficient detail in the programme, it has to be developed as such and you get to the point where you are using the model to detail the programme.
Model Based Planning good way to go, but find models are rarely developed enough to start planning like that, but there is a point on a project when both planing and models come together and models usually shoot past the programme in detail. I normally find I am called in last minute and by then boots on ground the model is super detailed and I am fighting to get it to work in the sofware as it is too large.
I appreciate that BIM isn't a model, its data that can take the form of a model or a spreadsheet.
My point is that a model can have too much data to programme so you need to have simplified models rather than than the central federated construction model as software doesn't cope with large infrastructural details that you find on say Rail projects.
As far as a single programme to run the 4D model sure, but the 4D schedule will always have more detail than the high level contractual programme. The 4D programme should be fed by that contractual programme, but often as you say you find the 4D schedule pushes the level of detail in planning from the model. You can't change the contractural programme, but will change the construction programme.