Microstation V8i Clash detection question

Hi all,

Im setting up a big clash detection file in Microstation V8i - its roughly 25 models clash checking with one another.

We are generating around 5000 individual clashes which need to be assigned to the relevant people. 

I expected a lot, but this is going to take a huge amount of manual work to get through.

One thing that we have seen is that many of the clashes are very, very small, say elements which are 1-2mm clashing with one another.

What I wanted to do was set a 'negative soft clash' - an acceptable limit for elements to clash with one another - say for example 5mm.

I know that you can set a soft clash which will flag up if elements are a certain distance apart - but struggling hugely to find if this is possible the other way around.

Im sure it must be something to do with the rule bases - but cant make heads or tails of it.

Many thanks, Peter

  • Hi Peter,

    The rules work best for eliminating clashes based on item properties. For example if you found that you had a lot of clashes caused by equipment that was set 1mm below floor level you could set up a rule to ignore any clashes between equipment and floors. That really depends on what type of clashes you are seeing and which ones are the important ones for you. Hope that helps.



  • Peter,

    Have you tried using the "touching tolerance"? (Job -> AdvancedSettings). That's attempts to shrink the clashing elements by half the distance specified and recompute the clash. That's really a best effort algorithm - it could fail in some cases as the elements fail to shrink, but it does work in many cases.

    Hope that helps.

       
    This is a test

  • Raman,

    Could you give us an idea of the type of elements that would 'fail to shrink'?

    Many thanks
  • If the shrinking causes loss of geometry like edges/faces - could happen if there are say rounded corners, or if the touching tolerance specified is too high, etc. The algorithm cannot compute the "penetration" distance, and uses these "tricks" to *try* and suppress typical touching cases.

    Like Mark mentioned earlier, the more robust way is to use the connectivity information (or any other property/relationship information on the Elements as seen in the Items Browser) where available - e.g., many Plant i-models do have sufficient information on connectivity, and we have some rule templates for suppressing clashes detected between connected elements.

       
    This is a test

  • Raman,

    ". For example if you found that you had a lot of clashes caused by equipment that was set 1mm below floor level you could set up a rule to ignore any clashes between equipment and floors. "

    I don't think this works in reality. if a piece of equipment is 1mm below the floor level then I would agree it would not be a problem. But if the overlap is 5mm that this needs to be picked up and dealt with.

    The problem is how to sort the clashes by overlap or 'penetration' distance... not about what is robust or not.

    Regards

    Dominic