Monday, April 29, 2013

How to Mess up a Revit plan view...Fat chance!

You know I would have bet a million bucks that somebody in our office would never screw this up...but it happened, so let me explain, and tell you how to fix it.

Our example includes a project with multiple small buildings in one file, at the correct elevation and location on a site. One building's ground floor level sits 3' higher than an adjacent building. Normally, when you set a project up, you would link the architectural model, then copy/monitor the levels from the architectural model to have one common set of levels. From the copied levels, you would create a floor plan view for each level, for each building.

Now stop and think about this - how would you do it in 2D AutoCAD? You'd take a site file showing the buildings, and either do a separate drawing for each floor plan (old school) at 0,0 in each building. But if you were doing both buildings in one CAD file, you'd be tempted (hold on) to create one plan viewport around one building on a layout tab...then copy the viewport, and pan over to the other building...all while keeping that viewport the nice, same size. This results in EPIC fail on the BIM test.

In 2D CAD, you can get away with this - but you can't do this in Revit - why?

Simple - every plan view is associated with a level, in most cases, a primary datum level at a specific elevation. Everything you place in the view is related to the level associated with that plan. Even hosted items can give off data that relates to the floor plan level, such as an offset elevation on a wall. But if you take a view that's associated with one level, and simply change the crop region around another building (which has a primary datum level at a different elevation), it's going to be wrong.

So here's where the problem occurs. For example - a user adds a pipe thinking that 210 Basement has the 210 Basement level as the associated level. So they're drawing a sloped pipe to what they think is 7' above that level. But in the view, since the 210 level is actually 3 feet lower than where it really needs to be. So the pipe is drawn at 10', not 7', causing additional work needed to change the pipe to the correct elevation.

You can change the associated reference level to get the right elevation, but it's something you're forced to stop and think about...and do a little math. Make it a really odd number...and you're really messed up.

And guess what - you can't change a plan views associated level once it's defined. (BTW - I did try to do this with a view list, by including the associated level...but no joy on that approach). You can also screw this up on single building projects - by copying a lower or upper level plan, and then changing the view range for the view properties. This is also a massive fail - since non-hosted objects display relative offset heights from the associated level...ugh...

So the fix for the user is to create a new view that's associated with the correct level, and then copy and paste generic annotations like text to the new view. Tags and dimension should be re-created, but these guys are pretty quick to make again.

In the end, it boils down to a simple thing - when you are setting a project up - whether it's one building or multiple buildings - make sure you start by creating a primary floor plan view for each level. Make sure it's associated with the correct level. If you are duplicating views to save some time, ALWAYS check that associated level. This keeps the issue from spreading like a virus to the rest of the project.

PAY ATTENTION to the details...cutting corners catches you every time...

later - David B.

Wednesday, April 17, 2013

Revit 2014 Notes and News...

With the product launch of Revit 2014, there's a lot of activity going on at Autodesk. I'm happy to report that we (Gannett Fleming) are wrapping up a few models for Autodesk that will be used as a dataset for demonstrating the product for this release. The building, which is a small medical facility, is intended to show how a model would be defined and leveraged across all areas of a design project.

One of our tasks was not to create a completed design, but more of a 80-90% complete design, complete with flaws and design issues that might occur during a project. So there are some conflicts, a few ducts that need to be sized, and some fairly complicated duct and pipe routing. We also include electrical system components that help demonstrate 120/208 and 277/480 voltage systems, and how to create a distribution system. Schedules include lighting, panel, and space/zone design schedules.

While primarily using out-of-the-box families, we also brought in examples of manufacturer content from Mitsubishi Electric.The HVAC system is designed as a variable refrigerant flow system. This system utilizes traditional supply and return ductwork systems, and room specific units that utilize makeup air from an energy recovery unit. The zoned systems also include demonstrating how a make-up supply air system can now be connected to a return air system. This is an improved feature in 2014 - in previous releases, the systems that are connected together all had to be the same type. You can now connect ductwork between these systems, but the sizing tools become disabled. We added a system connector family as an example, to demonstrate how you could maintain system separation and maintain the integrity of the system for sizing tools, and still connect the ductwork.

The architectural model includes a variety of finish materials, and allows the user to experiment with different design conditions easily. We also worked with Autodesk consultants on the design to create an asymmetrical design, including small variations in levels. The structure combines both concrete and steel components, to help Autodesk demonstrate the different design tools in Revit Structure.

All in all, it was a great learning experience for us as well. It helped drive home how important having a single, coordinate shared parameter file was on a project, which is something we put into place a few years ago. We included an example parameter text file based on the shared parameters exported from the Mitsubishi families to give us common voltage, number of poles, and  other shared electrical connection parameters. This helps us avoid the issue of having duplicate name parameters in a project, which can make defining schedules a real pain.

One of the biggest improvements for us came with the graphics systems. I've been running Revit 2014 on a three year old Dell Inspiron 14R, with an i5 processor, 8gb of RAM and Intel HD onboard graphics. I didn't have to wait for views to regenerate themselves, even in more complex views such as a transparent 3D model. File opens and saves were also faster. For someone who hasn't had the money to upgrade their systems, this release doens't mean the end of the world - as long as you keep your models compact. I haven't tried it yet on some of our larger, more complex projects, but I expect similar improvements on performance.

Rendering is also greatly improved, whether you are working on your own workstation or in the cloud. A simple  medium quality rendering using exterior only lights took about 5 minutes to produce the image above, even on my old workhorse.

So when you get a chance to watch one of the Autodesk demos, check out the model (and promise not to laugh too much - remember, I'm not an engineer, I just play one on TV). Hopefully it will give you an idea of just how far Autodesk has come with Revit for all areas of design - and that you get as much out of it as we do. 

Think you can guess how much time it took to create the model? If you can, you win - well, nothing of real value other than a pat on the back...I'll post the actual time up later as a comment - you'll be surprised!

thanks - David B.