Description
Principaux enseignements
- Create a library of standard symbols for use in both AutoCAD and Revit
- Set up templates to use standardized colors to represent MEP systems in both AutoCAD and Revit
- Define CAD standards for use in both AutoCAD and Revit
- Configure bespoke settings for exporting dwg files of Revit drawings
Intervenant
KIRSTY CHILDS: My name is Kirsty Childs, and I'm a BIM manager working for Tetra Tech in the UK. I'm going to be talking to you about some of the key points we've learned on our journey to standardize the way our drawings look, whether we produce them in AutoCAD or in Revit. I've always worked with building services engineers since my first role in the industry as a CAD operator over two decades ago.
So I'll be speaking from an MEP perspective, but I hope there will be lessons we learned along the way, which will help those who work in other disciplines, too. In 2017, before we became part of the Tetra Tech family, I was invited to create a Revit template for use by all of our MEP design teams. We had a BIM implementation team who'd noticed that across our offices in their various geographical locations, not everyone was using the same templates, or the same blocks from families, and not just in our department.
This slide represents the way that resources, such as Revit families and AutoCAD blocks were being shared across the offices where we have an MEP presence. The difficulty we had was very similar to the problem that a common data environment is designed to deal with on BIM projects. The way in which our resources were being shared, there was no logic to it.
So the BIM implementation team came up with the idea to create a common area in which to share our resources. We call this area the Shared Content Library, or SCL, for short, because BIM managers love an acronym. It works very much like a common data environment because, although, we encourage everyone to contribute to it, all content goes through an approvals process before being made available to the rest of the team.
Everyone was to be given access to the same content once proved. We worked with our IT team to make sure that, where possible, the software was pathed to automatically point to the shared content library, and this was included in our software deployment. But the SCL still needed to be populated.
We didn't want to just throw everything in there. I was provided with a core template, which was also shared with our architectural and structural teams, and I was asked to focus on using this as the basis for a standardized MEP Revit template. This challenge expanded when the system we previously had for managing our AutoCAD standards suddenly became unusable following upgrades to Windows 10.
It was agreed that the SCL would be used for both Revit and AutoCAD content. So we decided to use the opportunity to look for a way to standardize the appearance of our drawing output across both software platforms at the same time. As an illustration of the challenge we were facing, here are just a few of the examples I found of the mismatch in symbols that were in use.
The colored ones are from a Revit project, and the monochrome ones are from an AutoCAD project. I found at least two symbols in use for most components, if not more, because they varied between offices, as well as software platforms. On top of this, we had one office who insisted that all extract duct work should be blue, whilst another maintained that its supply duct work that should be blue.
It was clear that all of our CAD templates and standards needed revisiting and redefining, something we've done more than once over the years, most recently, when we became part of Tetra Tech and we revisited our templates as part of our rebranding. I know some people might ask, is that necessary?
If there is consistency across the same project, or for the same client, does it really matter whether all your offices are using the same content? We decided it did, particularly, because over the last few years, the geographical boundaries between our offices are being broken down. At Tetra Tech in the UK, we operate a hybrid working policy.
So rather than always sitting at the same desk, in the same office every day, we're encouraged to split our time between office and remote working, be that at home, at a client site, in the local library, coffee shop, wherever is the best fit on the day. This has had an impact on the way that we organize our workload across the MEP team. Our offices aren't the silos they used to be.
Projects are no longer seen as belonging to a particular office. We could have an electrical engineer in Edinburgh or Leeds working on the same projects as a mechanical engineer in London supported by a Revit technician in Manchester or Belfast. Because of these changes to the way we work, it's become vital that everyone in the MEP team has access to the same resources to maintain the consistency we desire.
You may also ask, why not just use Revit for everything? Well, some of our projects just don't lend themselves to that, as strange as that may seem to me as a BIM manager. We still work on projects, such as plant room refurbishments, or projects where we may only be replacing an old boiler, what we call our small works projects where our client's existing information is in 2D cut format, a format they use themselves and are not ready to-- or not in a position to make that switch to another format at this time.
We could import their existing drawings into Revit work on them in 2D, and then export them into DWD format again. But when we attempted this on a project, it proved to be a very time-consuming process, and risked pushing the project over its budget. So how to begin to tackle this problem?
But rather than starting from looking at what resources we already have, it's been more productive to start by asking what the building blocks are we need to deliver our projects. Again, this may be my inner BIM manager coming out. BIM projects should start with the client asking what information they need, not what information they have now. I've approached our CAD standards with the same mindset. It's about who needs what, and making sure they have access to it when they need it.
Some of these requirements will be company-wide, and some of them will be specific to your department. Fortunately, for me, the company-wide requirements were dealt with in the core templates that we were given. These included title blocks, textiles, dimension styles, and line types.
These are included in core Revit and AutoCAD templates, meant to resemble each other and given the same name, making them recognizable and familiar when switching between software packages. Content naming convention defined is also a good idea, particularly, for naming content such as Revit families. Initially, we had referred to Revit categories when naming families, but we now use a British standard that references IFC classifications for naming library objects, making the name suitable for inclusion in COBie schema, which is a requirement of the UK government BIM strategy. It also makes our naming convention suitable for use in any software platform.
Some of these company-wide standards will be linked to your brand identity, so shouldn't be developed in isolation if, like us, you belong to a multidisciplinary consultancy. Fortunately, these haven't been provided left me to focus on our requirements as an MEP team. The top two items which immediately came to mind were drawing symbols and system colors.
We also identified that the team would benefit from having a central resource for standard details, schematics, and colorful legends. These would be supported by documentation of our standard methods and procedures and training materials. Once we had a list of what we wanted to provide, we then gathered up all of the resources being used in each office and started to assess whether or not they were suitable for inclusion in our shared content library.
Initially, I set up a working group to look at what we could use from our existing resources, which included representatives from each MEP office. It was very useful, to a point. For example, a loss of the standard details we collected over the years are still in use now. Everyone has access to the same details, and they are available in both AutoCAD and Revit.
At first, we used the AutoCAD versions in Revit by linking them into projects. But we now have them available as Revit files, as well. We use the process of copying these details into Revit as a training exercise for apprentices.
However, in terms of drawing symbols and system colors, it became clear that on this occasion, democracy was not going to work. Each office was so used to their own way of presenting drawings that a compromise didn't seem possible. At the same time as some heated debates were taking place, we were in talks with a company called MagiCAD about delivering training to use Revit, and their plugin for Revit to our engineers.
One of their teams suggested an alternative approach, that we adopt an industry standard. We've investigated this previously, and there didn't seem to be just one standard out there that covered all the symbols and system colors that we wanted to regulate. However, MagiCAD introduced us to the work of the Society of Digital Engineering, which is part of the Chartered Institution of Building Services Engineers.
They've been working with industry partners such as MagiCAD to create a standardized set of drawing symbols and system colors that can be applied across the building services sector. This is just what we were looking for. Although, this meant all offices having to change their standards, it also meant no more heated debates about what color an extract duct should be. So our head of department made the decision to adopt the CPC standards across the board.
Alongside this, we were implementing quite a big change to our workflow to avoid a lot of double handed work, meaning that our engineers were drawing up their designs in AutoCAD, or even by hand, and then passing them on to our technicians to be modeled in Revit. The decision was taken to teach all our MEP engineers how to use Revit and how to use the MagiCAD plugin I mentioned earlier. This enables our engineers to use Revit for calculations that are based on British design standards.
The engineers are encouraged to use these tools to design directly into Revit. I was responsible for organizing and rolling out training for these engineers across three of our offices and had project work at the same time. The upshot of this was that whilst we'd made a lot of decisions about our standards and templates, implementing them was taking far too long.
We outsourced much of the work we needed on our Revit template to the MagiCAD team. Since then, I've managed any updates to it, including rebranding it as a Tetra Tech template. However, in terms of our AutoCAD standards, sadly, our M&E CAD manager passed away during the lockdown and hasn't been replaced.
She's working from home in March 2020. I started holding weekly meetings with the technicians and BIM managers in our other MEP offices. We still hold these now.
There are only two of us in this group who've been involved in this standardization process since it began. Most of us have only ever met virtually, so these meetings have been key in pulling us together as a team. We've been working collectively to bring our AutoCAD standards back up to the same level as our Revit standards. And having what we wanted to achieve set out in advance has helped us to stay on track.
This same team have been working together to create a library of guidance documents to explain how our templates work and describe the processes and workflows that we use. Eventually, we hope that these will be embedded with several sharp video demonstrations, following feedback from one of our apprentices that he'd be far more likely to watch training videos if they were short enough to be a TikTok. This guidance will be hosted on a dedicated page on the company's SharePoint site.
I'd now like to demonstrate how we implemented some of this process. I'm using a model and a drawing created for demonstration purposes only, and using the most recent versions of the software that we have rolled out for general use. These are Revit 2022 and AutoCAD 2019.
Getting the symbols into AutoCAD was a relatively straightforward process. We received the symbols from CPC as DXF files, which we converted into annotated blocks. We started with a drawing file for each type of service, which we use as a legend. We open the DXF file for each symbol, and then save this as a DWG file to a folder on the shared content library with a new name as per our object naming convention.
This was perhaps the trickiest part of the process, as the way the IFC classifications are organized doesn't always lend itself to MEP objects in a familiar way. We then inserted the file we just saved into a legend file as a block, and positioned it in line with the other blocks. We then open this block with block editor, changed it to an [? annotative ?] block, disabled the option to allow the block to be exploded, and added the relevant description from the CPC standard symbols document.
We then saved the block again, overwriting the block we previously saved to the shared content library. It's a simple process and, perhaps, a bit laborious but, again, a task we found useful to assign to new team members who are still building their confidence using the software. Once legend is copied into drawing, the box appear in the dropdown menu.
Alternatively, they can be dragged and dropped into a project from the shared content library using the Design Center. We've made sure that the content of the blocks is on layer zero, and the color set to bilayer so that when we use the same block in more than one system, the [? colorful ?] of the block can be taken from the color for that system layer.
Unfortunately, the task of amending our Revit families so that they use these same symbols seem like it might be the most time-consuming part of this whole project. This is because they're embedded into the families of the items they represent. The families have been created by so many different people and pulled from so many other sources online that the way they'd been made was very inconsistent.
We also noticed that the parameters these families contained did not always align with each other, particularly, families downloaded from manufacturer's websites. However, the MagiCAD plugin gives us access to a vast library of Revit families for which the symbol can be selected before the family is even created and inserted into a project. The content is all managed through a data set.
Here, we see the same items that were in the AutoCAD legend. If we look at the properties of one of these in more detail, you can see that we've selected the CPC symbol to be assigned to this Break Glass [? bond ?] for use in both planned views and when used in a schematic. This item isn't turned into a Revit family until the user chooses to install it.
So we can add the name we want the application to use when it creates our Revit family before it's even created. We've used the same names that we use for the AutoCAD blocks. We've also chosen the option to size the symbol by the scale of the drawing on which it's being used so that it works just like the annotated AutoCAD blocks.
This feature will be built into the family that's created. To maintain consistency, each new Revit project is set up with a common data set, which is also stored in our shared content library. We cannot always guarantee that all users will have access to MagiCAD at all times due to the number of licenses so we've also created a family for each of the elements included in our common data set. And these have also been made available in the shared content library. Once a project is set up, a project specific data set can then be created to add any content that isn't likely to be reused.
Moving on to system colors, these colors were also specified in the CPC standard for most systems that we designed, and they also include guidelines to select new colors for any systems which might not be listed in standard. I've used a domestic water services pipework joint as an example. You can see from this extract that a darker color has been specified as the outline color, and a corresponding paler one as a fill color.
For our own purposes, we knew that if we were working in AutoCAD, we would always represent the pipework as a single line for which we'd use the outline color. So we looked at the standard layers we already had, the names of which are based on the British standard, and we amended the colors assigned to these layers to match the CPC standard. As this means using RGB values to set the color, we've moved away from using pen settings in a plot style to determine the thickness that a line will print.
The line thickness and the color are now set by the layers properties. This has worked quite well, especially, as it's now quite rare for us to print a drawing. Most of them are only viewed as PDFs.
The same colors would be applied in Revit was far more contentious because there are so many different ways to achieve this. We dismiss the idea of using a system color scheme. This worked to a certain extent using the fill colors from the CPC standard, but we had to find a different way to add an outline color.
This method didn't really work for early design stages when we'd usually use a more cost level of detail. Some of our team favored the use of filters, but others are not very fond of these because in our legacy template, there were so many filters being used for so many different purposes that you knew if you'd modeled something and then you couldn't see it anymore, nine times out of 10, it was being picked up by a filter without your knowledge and switched off. This method does work well, though, if it's well-managed. And it's more adaptable now than when we began this process.
However, on the recommendation of MagiCAD, we went with a third method. We decided to create materials for each duct work system, making use of the quirk in Revit that our system can have a different material to the elements it's made up from. The pipe is modeled as copper pipe, as are the other two pipes shown.
The outline color and the color used in a course view when presenting the system as a single line is set by the visibility graphics override, not in the view template, or by using a filter, but in the [? tight ?] properties of the system as demonstrated here. However, the fill color is set in the material that is applied to the system. So when we change to a fine view, you can see that these three pipes are all still copper pipes, but their system has different material assigned to it, and this is where the fill color comes from.
This method works equally well in 3D using consistent colors. And should you wish to view a more realistic representation, the copper material is maintained, shown here with the outline color still giving a hint of the system the pipework is for. Our final puzzle piece was, how do we get a DWX-- sorry. How do we get a DWG export from Revit to look like one of our AutoCAD drawings?
This is something that we often get asked to provide when handing our drawings over to a contractor who'll be developing the next stage of the project and cannot guarantee that everyone in their supply chain will be able to use Revit. Before we investigated this, not much attention had been paid to the export settings for these DWGs and how these can be customized. Here, I have an example fire alarm layout drawing produced in Revit, purely for the purposes of this demonstration.
This is what the drawing looks like when exported as a PDF. However, when we spotted the same drawing from Revit to a DWG, without changing any of the settings as they come out of the box, as it were, it looked like this. She's far from the look we've been trying to achieve.
We've recently had comments from a contractor about a similar drawing, not about the colors, but about the layers in the drawing, which are not to the British standard. So we started to investigate how the DWG export settings could be amended to better suit our purposes. These settings are accessed using this button with the three dots in it.
This will open this dialog box where you can use the dropdown menu to select from a few different layering standards, or load in one of your own. We chose the British standard. Then, on the Colors tab, we changed the settings to use the colors as they appear in the view that's been exported.
We also changed the units and coordinates to reflect the way that we work, and then exported the drawing again. This time, we got something in AutoCAD that was much closer to what we'd expect to see if the drawing had started its life in AutoCAD and looked more like the PDF from Revit. This still has its issues.
One problem with this method that can't be seen until you go into the model space of the drawing is that those symbols that we're seeing are not the blocks that we would see in AutoCAD. They're just a collection of colored lines. We've not found a way to resolve this.
However, the layers do resemble what we're used to seeing, although, they are virtually all the same color. We could resolve this by using the color IDs of each layer when exporting from Revit. But that would mean finding the closest match to the 255 colors available in AutoCAD, rather than using the RGB values we've been used to using in line with the CPC standard.
If we were to decide to do this, then we could also make use of the layer modifier function, which enables us to export each pipework system onto a different layer, rather than all being on the same layer. This is achieved by adding the system type to the end of the layers name. Each of these systems can then also be assigned with a color ID. And then when exported into AutoCAD, both the system name and its relevant color are exported.
This is part of the process that we are still perfecting and will be linked into our review of our layer naming, which, for the UK market should now incorporate unit class classifications. As I said earlier, we're regularly revisiting these standards as software changes, BIM standards are updated and revised, and our client's requirements change. So it is worth revisiting the process of defining your CAD standards regularly, and researching software advances that may help you to manage these.
I hope you found this useful, and that you find something that you could take away and implement within your own workplace. Thank you for listening.
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