Why is Clash Detection Still Black Magic?

I dont like the term Clash Detection. If your told or you ask for clash detection, what is being asked for? What is involved? What are the outcomes?

Your instant thought is Navisworks, clashing all of MEP against all of structural and ending up with a report so long you wish you hadn`t woken up (Whether that be the person who produces it, asked for it or is responsible for it)

Today, clash detection is still debated on social media and the meeting table. Main Contractors asking for Clash Detection from designers without being specific, designers saying no without being clear on what they are saying no too. Nobody doing it apart from that BIM Consultant or BIM manager who is telling the Lead Designer where coordination issues exist when the Lead Designer sits back and waits to get told

What is the problem?

The problem is the increase in waste through duplication of activities by different roles. We are also not being clear what we want and so new roles are appearing doing these ambigous tasks that some argue duplicate those of others. We are often appointing BIM consultants to do these task because design leads don’t want to do it as the details were not clear. This can end up with 2 parties being responsible for design coordination in some regards when you actually find both are finding design issues, reporting them and bringing them to the table. The difference is often only the technology the 2 use to achieve it!

The Design Lead is appointed as being responsible for giving the MC a coordinated design yet we have a “BIM Consultant” now bringing Coordination Reports to design team meetings that usually show the design lead hasnt given us a coordinated deisgn, and this is because they have identified issues with the design that the Design Lead failed or didn’t bother to look for. The amount of times I have been called to projects to help and I have no idea who is now responsible for design, who the design manager is because this BIM consultant seems to be doing both Design Lead and Design Manager role and who is actually accountable for checking, registration and resolution of design coordination issues. Its madness and its not uncommon. I often see design leads and design managers marking up drawings and coordinating around drawings and then the BIM role is off doing their thing in the model world, often disjointed with both 2D & 3D process not combined.

You end up asking the Design Lead at the end of the day “why haven’t you identified the issues the BIM Consultant picked up, some very critical” with him/her saying “we are aware of some of them, but we just mark up dozens of drawings. Your BIM consultant is responsible for producing a report, he should look at my drawings”. I turn to the project/design manager and usually say, “Can you tell me why you went for this designer who wants to do everything different to the project and often organisation objectives?” only to be told, “they were cheap”. And here we have it, the money you saved on this cheap consultant you spend on a £80k a year BIM consultant who is doing some of their job just in a different way. Congratulations.

So what is Clash Detection!?

I am not going to define it like many others do by wording it into a small paragraph. Everything should be defined by the activities/tasks that need doing!

So, when I ask for clash detection I don’t ask for “Clash detection”, I ask for:

• Provide a report of coordination conflicts that contains their urgency, the responsible party for resolution, date for resolution, image of the coordination issue
• Provide a visual representation of the design that includes the highlights of the coordination issues found above that is accessible to the whole project team without them procuring costly tools.

The above is very clear and simple, if I asked for this 20 years ago I would have got a hand filled in excel sheet and a snapshot of a 2D hand marked up drawing with some kind of link to the issue on the excel sheet.

I dont demand what tools should be used to undertake these activities (Minus the reporting tool which maybe a cloud based record database like BIMCollab), I ask them to propose their strategy for doing it, and I see if its acceptable.

So who does clash detection?

Consider the term Clash Detection doesn’t exist. And that all you have is the above 2 bullet points. Who usually does that? Forget BIM for a moment, I think many would agree its in almost every single Lead Designer appointment. If I went out to tender for a Lead Designer, and I asked them to provide an example for how they will achieve the 2 bullet points above, taking into consideration the the project is BIM Level 2 enabled and the client is really keen to get into this “BIM Thing”, which will I choose below?

1. We will not provide a list of coordination issues or a visual representation of the design
2. We will provide both the report and visual representation. We can do this via populating an excel sheet and attaching drawings with references from each issue linking to the drawing
3. We find that manually filling in excel sheets by hand and marking up drawings time consuming. We have found tools to make this process easier. We can use tools like Solibri to identify issues and easily export them to excel sheets for your review which contain 3D snapshots of the issue. This review can also be given to you in the form of a combined 3D design model that only requires a free download viewer to open. But for this to work, we need the whole design team to provide us information in the following format using the following standards …..

I will be honest, the 2nd option is tempting, they are cheaper. My QS is likely to go for them. But I must also take into consideration that we are a BIM Level 2 enabled project and my client is surely going to ask why are we not using the models to their full potential.

The 3rd option will always be my choice, Its clear they have invested in new technologies. But my QS decides to go for the 2nd. Later, my clients and the team actually want to start looking at the design in 3D. The consultant I have isn’t able to accommodate so I have to now procure a BIM Consultant of some kind…. “HEY MR QS, That 5% saving is to be diverted to a BIM Consultant now that actually needs more cash, and is somewhat doing the same job as the Lead Designer just using different tools”

I believe detection of coordination errors and reporting of those errors are part of any standard appointment. The only thing that’s different is the way its done. Some designers have moved to modern methods, others have not. Sometimes the issue is actually because Clash Detection hasn’t been defined or isn’t defined as I defind it above which can often result in moving outside of standard appointment scopes.

So When Should a Lead Designer perhaps say No?

If Clash detection has been defined differently to the way I have above, then the following can be grounds for why Clash Detection is avoided by Design Leaders.

• Main Contractor asks for Navisworks or Navisworks models when they didn’t bother to ask the designer what tools they use already i.e. designer isn’t Autodesk familiar and use ArchiCAD and actually uses Solibri, Tekla, Zoom, Asite for clash detection.
• Terminology is used like “Must generate a list of ALL clash issues”. This is a rubbish, is a drain pipe a clash when going through a floor at an early stage 3 design? Design development will resolve most of these issues. So the contractor should have asked for what they used to ask for, a list of the main coordination issues that are likely to impact the project for review at design team meeting
• They badge Clash Detection under a fictional role called BIM Manager or God. This has its own problems because the Lead Designer is thinking to themselves “BIM is more than just design, so basically your asking me to go beyond just my standard role” and you will be rightfully told where to shove it.

So what can be done?

Main Contractors

Stop using BIM Buzz words. Say exactly what you want from your design lead. Clash detection isn’t it! Tell them what you expect like how I have defined it above and then ask them how they plan on doing it. If they old processes, remind them they are on a BIM Level 2 project and we are looking for digital/BIM enabled consultants

Stop procuring design consultants/contractors before you start having a conversation on BIM! This is very important. If you procure a designer without checking their capabilities or their approaches. Then don’t start getting angry when they start saying No to anything you say about BIM. Its their fault they haven’t modernised which is their own problem. Its not their fault though that you agreed to appoint them but didn’t bother to see if they can do some of the stuff you didn’t define to them from the beginning

Don’t tell your designers how to do their job. Tell them what you expect and see what their proposal is. Stop telling them how to clash detect, what tools to use, what they need to clash check. They tell you this, and you agree or work with them to a solution that suits you both.

Lead Designers

Just because I am a contractor doesn’t mean I don’t understand how you feel. You are getting a lot of crap thrown your way at the moment that doesn’t make sense, sounds ambiguous and your natural reaction to anything that isn’t clear is *RISK* so *AVOID*. My best recommendation is to draft a “Coordination Strategy” that your organisation has decided to adopt as standard using the latest tools and processes. If you have decided to not to invest in BIM then you have more problems than you think. But if you have, think about what you are asked to do already, then propose how you can do it that shows your commitment to BIM and collaboration without taking on extra responsibilities. Get this proposal approved by the project and incorporated into the BEP. If not of that includes a process for how you spot clash issues, record them and make it visually presentable to the project for complete understanding using BIM in some way, its not going to go down too well.

Sub-Contractors

Its not the lead designers job or the job of the main contractor to do your job. You like the lead designer have a role to produce information that’s accessible in the formats required. The coordination process is put at risk if your information isn’t in line with the project requirements. Make sure that you have a process in place for how you deliver information in accessible formats and a process for how you check your information is coordinated against everyone else.

Conclusion

So lets stop talking about BIM and buzz words that are linked with it. Define what you want or what you offer and ensure that it aligns with project objectives. The projects I have supported and ensured they follow a disciplined, logical process usually result in no roles having any changes to their responsibilities. The only change is the greater use of models and technologies. If you are unskilled in either, then this is a problem for any subject.