How Clash Review Saved Thousands for My Family House
May 7, 2024 at 7:00 am,
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A clash review is a process in which 3D models from various project disciplines are merged, and using various methods, design errors are identified. Checking can also be performed on individual models. Essentially, this process constitutes quality control of the design, but from a different perspective.
Once issues are identified, they can be prioritized and resolved. This activity can be undertaken early in the design phase when partially developed models are available, thus preventing time-consuming rework later on.
The outcome of this process is a significant reduction, or even complete elimination, of unexpected and costly errors during construction.
What Is Needed to Perform a Clash Review?
What Is Needed to Perform a Clash Review?
To conduct a clash review, 3D models from one or multiple disciplines are required. If only one discipline, such as architecture, is available, you'll be limited to performing only basic checks, primarily those that might identify issues affecting quantities.
However, for more comprehensive results, models from additional disciplines are necessary. At a minimum, these should include architecture, structural elements, and major MEP components (such as pipes and equipment).
Methods to Do Clash Review
There are two methods that can be utilized to find clashes:
- Manual: This method involves using simple software such as free model viewers and then employing tools like walkthroughs, sectioning, and hiding objects to identify any issues. While this method is advantageous as it does not require purchasing expensive software, it is prone to errors since you might miss some clashes simply because you did not see them.
- Automatic: This method employs tools that facilitate finding issues automatically with defined tolerances. After conducting the checks, you receive a list of clashes and then need to group them and identify the major issues. Typically, this method is carried out using paid tools like Solibri Office or Autodesk Navisworks. However, there are also free-to-use tools with limited but useful clash detection functionality, such as OpenIFC Viewer.
To achieve the best results, both methods are usually employed. This is because not all issues can be found automatically; for example, there could be an obstacle in front of an openable window, which is not technically a clash and might not be detected by some tools.
How Clash Review Saved Thousands for My Family House
In my case, the architectural model was created by the architect, the structural model was done by me, and MEP models were developed with the assistance of external help and myself. From my experience, errors in 2D drawings are inevitable, regardless of the building's size. This was also evident in my own home. Some of the most significant and potentially costly clashes were the misalignments between the architectural and structural components, as well as issues between the structural elements and MEP systems. Here are a few examples:
A missing opening in the structural model was only noticed after HVAC ducts were modeled. These clashes emerged when the structural design was nearly finalized. This issue compelled the structural designer to revise the structural frame. Rectifying this error during construction would likely incur significant costs.
There were several instances where the structural elements were not aligned with the architectural design, such as the terrace being a different size in the structural model compared to the architectural plans. Similar discrepancies were also found with the canopy columns and various other components.
Modeling MEP objects revealed that there was not enough space beneath the ceilings in some locations. Since these issues were identified promptly, they could be resolved in the most aesthetically pleasing manner.
The combined models also identified misalignments and errors between the architectural and structural components, as exemplified by this case where the sink was not located in the expected position.
Conclusion
Clash detection and review are fundamental aspects of utilizing 3D models, offering significant potential for cost savings even in small-scale building projects. This was evident in my own house. The result of conducting this activity was the absence of major design errors during construction, thus preventing cost increases. My optimistic estimate is that several thousands of dollars were saved as a result. Moreover, it's worth noting that we did not have to make any difficult compromises, such as reducing ceiling height, which quite often happens in uncoordinated design.