Synchro was developed not purely for 4D visualisation, rather 4D was always one leg of a 3 legged stool; 4D was no more important that the other 2 legs (collaborative top-down/bottom-up planning and management of risk) and this is largely born out by its impact on the delivery of projects. Software is undoubtedly driven by the customers it serves and as such it is and remains predominantly used for the aquisition of new business rather than the downstream delivery of projects for which it was designed.

Synchro (or START as it was originally named) was born out of the MidCity Place project which also was the foundation of the DTI report "Rethinking Construction". That report exposed a number of weaknesses in the construction process that some may still identify with and solutions for which were designed into the Synchro product. So for anyone who has invested in a licence you might like to know what you actually have bought and what it could actually do for you.

• Collaborative planning - (excluding issues relating to the availability of design information) Development of schedules especially those falling into the early "level" categorisation are described as top-down; projects are split into phases and locations (or vice versa) and high level tasks represent the distinct tasks required to deliver projects within those defined phases/locations. All good so far. As information is distilled perhaps as a result of improved design information those top-down schedules can increase in detail. At a certain juncture packages of work will be 'let' to sub-contractors which is where the issues start to creep in. Sub-contractor schedules merged into main contractor schedules represents bottom-up planning if coordinated and managed by processes then a happy marriage can exist that avoids the pitfalls that are described below:  

1. Sub-contractors are often given little or no visibility of the tasks they are dependent on, or that will be dependent on them.
2. They are often not given and asked to respond to a set flow of work.
3. Their schedules are often not 'fed in' to the main contractors schedule
4. There is a lack of visibility fom which they are able to respond to change
5. Impact of change is poorly recognised due to the lack of integration
6. Risk is inherently built into tasks (impact of which described later).  

Synchro has the framework to enable effective top-down bottom-up scheduling. It also offers 'supply chain perpetuation' allowing through permissions for the control and ongoing definition of tasks to be ceeded from main contractor to sub-contractor to sub sub-contractor etc etc. This methodology addresses many of the issues highlighted. Visibility exists as they can view all project tasks or sub groups of tasks at all times; flow of work is inherited and forms their boundaries for delivery; schedules remain integrated but always flexible to encourage the registration of intent or change on a real-time basis; risk is negated as an integrated schedule that is owned by, contributed to and always up to date is far easier to buy into and can be deemed potentially more relibale (it also exposes when and why unreliability occurs which can itself be fed back into the loop).

• Management of Risk - Risk management in Synchro follows the "Critical chain" methodology. Risk is a touchy subject in construction; It is introduced at all levels of scheduling from the first to the last to the point that virtually all construction programmes can be characterised as "planning to fail". Is this bad? not really, few would disagree that having an "up-side" is far better than having a "down-side"; yet even with the most risk loaded schedules, failure is all to often knocking at the door. Why? simple really, if you plan for risks to occur your schedule represents the late availability of space and start of successive tasks; if no risk materialises in the delivery of a task then do sub-contractors sit around waiting days for a new work area to become available, or do they re-assign their workforce to another task that could be started but was not planned to do so? My experience is they move onto a new task (they want to get 100% utilisation of their workforce and quite rightly so). The inevitable consequence of what might at first glance be a positive change is that the impact is not fully accounted for (lack of integrated schedules); work flows become disrupted (out of sequence) and the positive quickly turns into a negative. So what are these built-in risks predicated on?

1. Lack of visibility (who, what, where and when are other trades working).
2. Lack of integrated schedule and up to date schedule offering reliable expectations.
3. Lack of management control.

Once again, Synchro was always designed to address and overcome these issues. The mantra "schedule tasks and manage risk" used to be firmly central to the sales argument. Referring back to the 3 legs of the stool it is clear that without a collaborative approach to planning and the universal interpretability of 4D risk management will remain an elusive persuit.

In conclusion. "Rethinking construction" was all about the potential to introduce Automotive thinking into the construction industry; practices like "Just in Time" (JIT), centralised material handling and many more rely largely on there being a reliable schedule of work and reliable schedules rely largely on the previous messages.

So if you think the stool you are sat on feels a little wobbly then perhaps you need to fit the other two legs; you'll feel more secure and your share price may well reflect it!.

Lastly, there is progress in the world of 4D (which if you are reading this is probably because you use Synchro for '4D visualisation'. I use the term '4D visualisation' advisedly in lieu of '4D Simulation' as Synchro is not a construction calculator, it merely facilitates the association of 3D to tasks. 'Simulation' defined as “The construction of a mathematical model for some process, situation, etc, in order to estimate its characteristics or solve problems about it probabilistically in terms of the model”  will be the real game changer able to resolve schedules from the mere existence of 3D at the press of a button along with the required BOM/BOQ's, budgets, exports to planning systems and the ubiquitous 4D visualisation.