BIM creates different types of graphic errors
Raise your hand if you’ve had this situation occur:
A non-BIM user is redlining (pinklining?) a set of drawings created with BIM. They panic and freakout. They see an error that if it was done in 2D would be a disaster. Or the sign of complete ignorance. Can you imagine drawing a floor slab in the wrong location by hand? It’s a simple fix in BIM. Perhaps a slab got moved by accident in the final crunch. So instead of being at 0′-0″, it’s at 6′-3 1/2″. Oops. Embarrassing. But SUPER easy to fix.
Our problems are different
There are so many examples of non-events in the world of BIM that would be complete disasters in CAD or by hand. Part of this has to do with one’s relationship with the drawings. As we work we are looking at the model and most views, but sometimes (especially for preliminary sets of drawings) not every drawing gets reviewed in minute detail before printing. That’s not a sign of laziness, but a jumpshift in how one works. I don’t need to review every section before I print out the drawings because I can review them (or someone else can) to verify the proper display of information after the set is printed. More critically I have been looking at the information in those sections, though most likely in other views (3D, 3D sections, plans, details, other sections, etc). That means I can review the project/building/design completely, but not necessarily review the drawings thoroughly. And as the design develops it’s the evolution of the model data that is more critical for the resolution of the project than the graphic correctness of the drawings.
In the above example, the two problems (a glitch in the Morph Tool which was making lines show up that should have been hidden behind a wall and a slab that got moved) are both insanely fast to fix (hide individual edges of the Morph or turn off the layer and move the slab down in section). Should I have caught both before I printed out? Of course. Does it really matter that I didn’t? No. Except that it took my coworker more time to note and worry about the problems than it did for me to fix them. And that’s maybe the point I really want to focus on. These things happen. And it’s okay. What’s important is to train your entire team to look at drawings differently. They need to be able to read the difference between a minor goof and a major disaster. Because they don’t look the same as our old problems. Line weights resolved in one view are magically resolved in all views. An element out of place in one view will be fixed everywhere. People still redlining by hand don’t need to mark every instance of a mistake. Just in enough locations (one) so that the problem will be resolved. Because like I’ve mentioned before mistakes show up in multiple views, but they are still just one error. So a goofy hovering slab might be wrong in ten places, but it only needs to be fixed once. What a difference from the old 2D ways.
Oh and the best solution to this problem? Print sooner rather than later. Remember, the paperless, print-free project isn’t here yet.
TroyGates
VDC sessions are the replacements for redlines. Spend a day walking through the model with all disciplines and when you find an error, fix it immediately in the model.
Jared Banks
Agreed. Or even just internally walking through the model with the Architecture team. In the past few months I’ve done a ton of Skype sessions with design partners out of state. We just look at the model in ArchiCAD (whether it’s open on my end or their end) and design/redesign/find errors that way. SO much better and faster than print, redline, fix, reprint. Though there are still way too many people who just want to see print outs… old timers who ‘understand’ projects better when looking at sets of drawings.
David Duarte
Graphics issues tend to go away with increased modeling experience. Staff start to figure out what modeling practices consistently cause graphic errors in the set. They tend to develop better modeling practices over time. Once I was in the mindset that everything I modeled was eventually going to end up on paper I devoted more time toward discovering better modeling practices that would result in cleaner and faster models.
Jared Banks
David, thanks for your thoughts. A strong template decreases these issues tremendously. And BIM without a template is suicide.
Without a doubt, these problems are definitely more of an issue for less experienced BIM staff. Unfortunately Graphics are also a moving target. What one architect finds beautiful another finds lacking. So some of this is more about the person viewing the prints than the capabilities of the person doing the model and documents. As a freelancer and before that someone working in a firm with 15 designers with distinct opinions… well let’s just say it never ends! 🙂
Eric MacInerney
It is an interesting issue that can go deeper than what your colleagues think. What it comes down to is that in traditional 2D drafting, you have to choose to draw a line and if you did then it must mean something. In BIM, especially in sections, you get all the lines to show, whether they are meaningful or not. On a few occasions, I have had to explain to a contractor that the line he was so diligently trying to figure out what to do with was in fact a spurious line created for another view. Of course, better experience=better models=better drawings, but in the meantime we do need to educate all those who come into contact with the BIM model products.
Jared Banks
Well said. Thanks!
Nick Pacella
David, that is the beauty of integrated 3d modeling, it can be used to refine the design process and not just be produced as an afterthought.
Jared, what do you mean by a template?
As always, the more time spent up front the better the information will be in the documents. Unfortunately, some clients expect that BIM will lessen the time we need to develop our drawings.
Jared Banks
Nick, by template I mean both the starting file you use to create a new project (that has all your standards saved in it) and the over arching systematization of your design process. I talk about it a bit more here: http://blog.graphisoftus.com/archicad-education/tips-and-tricks/process-vs-happening-templates-are-not-optional
If each project is derived from one-off standards (pen sets, materials, composites, titleblocks, etc), then there’s a huge amount of waste.
Lucille Ancira
Great discussion on graphic errors. I like this article, thanks so much for posting this.
Jared Banks
Thanks. Glad you enjoyed it!
Adam
Good thought, and I can see where you’re coming from, but the major issue I have with this post is the fact that drawings DO matter, unfortunately. It is the drawings, not the model, which become stamped and signed contract documents for construction. The drawings are a legal binding document that is submitted to the owner, to the contractors, and to the governmental authorities. The model is not always handed over in the construction phase, and if released, there is no legal guarantee of accuracy. In the end, the drawings hold all the power.
Also, it is the drawings that are taken into the field by contractors who combed through them everyday, looking for discrepancies and lack of information, which in the end will make them extra money at the designer and owners expense. Bottom line, no matter how much I love BIM, until there is a fundamental change in the contractual delivery process, the drawings and specs will reign supreme.
So instead of complaining, make sure you allocate enough of your own time for review. And thank the person that redlined the drawings for you, he probably saved your company some money.
Jared Banks
Adam, never said drawings don’t matter! They do. A lot. And will continue to for some time. Though I imagine that will change one day.
The point isn’t about who caught the mistake or who caused the mistake, but about training the team to have a different relationship with the preliminary set of drawings. Of course if I had more time I would have caught the mistake myself. Or maybe I wouldn’t have because there were other more important issues to resolve at that stage of the project (and my time would be better spent getting other areas figured out and more put into the model and other details drawn, etc. etc.). Many eyes will see the drawings and catch errors. That’s great.
But if one pair of eyes doesn’t understand what the mistakes they are seeing mean, and spends too much time on them, then there is no money saved. In this specific instance, if the architect reviewing the drawings spent any more than about 3 seconds on those graphic errors then he was wasting, not saving money. Sure the best way to save that money would be for that error to not exist, but errors will always happen. So we need to be able to read them for what they are. And that is the point of this post. BIM creates different graphic errors and whether or not you’re the one at the computer, everyone on the team needs to understand the difference.
Think about this: can you imagine someone redlining a set of drawings derived from BIM and marking EVERY time a 2×4 wall has the wrong fill? That’s a 15-second global fix (or if it’s not, whoever made the BIM is doing something wrong). If the redliner doesn’t understand that, there is a huge waste of money and time.