This article delves into best practice workflows in CAD projects, focusing on the organizational structure of model files and how they are utilized in real-world scenarios. It explains the significance of XRef command within AutoCAD, demonstrating its critical role in maintaining up-to-date and easily modifiable project files across different teams.
Key Insights
- The article highlights the importance of organizing CAD files into three categories - plan model file, elevation model file, and section model file. These files contain all the drawn information which are then referenced into individual sheet files using the XRef command in AutoCAD.
- In a team setting, architects typically share the model file with consultants (mechanical, electrical, plumbing, and structural designers) through a cloud-based file sharing system. This allows consultants to reference the architectural model in their drawings, and ensures changes to the model file are reflected across all disciplines.
- In terms of best practice, the article underscores the utility of XRef Compare option. This feature allows consultants to see any changes made to the architectural background, enabling them to update their own drawings accordingly. This way, XRef helps maintain a network of connected AutoCAD drawings, regardless of project size.
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Let's take a quick break from our model to talk about a couple of best practice workflows that we are going to add into this course. This more closely aligns with how things are done in a CAD office, although each office might have a slightly different workflow.
In our previous class, we had a model file, which was what we called a floor plan. This model file should contain any information for what we call a plan view. So this could possibly contain information for a floor plan, roof plan, reflected ceiling plan, electrical plan, structural foundation plan, or any other information that would need to be represented in a plan view.
In most real-world projects, there are typically three different model files. These are the plan model file, elevation model file, and section model file. We will focus on the plan model file and elevation model file in this course.
Once the model files are created and the drafting is complete, we reference the model file into individual sheet files. This is done using the xref command in AutoCAD. The model file contains all of the drawn information, but each sheet file has independent layer visibility, which allows us to have unique sheet files for each plan view.
So I could have my architectural floor plan showing here, my roof plan showing here, electrical plan, structural plan, and so on. All of the information comes from one model file. Now, why do we need all of this information in a single model file? If I wanted to make a change, say move a door, add a window, or change the shape of a room, I would want those changes to show up on each of my sheet views for all of my disciplines.
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So how does this work when we work with a team? Very commonly, because some projects are large, we will work with a design team. In this example, you can see that we might be working with mechanical, electrical, plumbing, and structural designers. The architect would be required to provide a background or underlay or overlay for each of these consultants.
The architect would then take their model file and share it with the consultants through a file sharing system, which is typically cloud-based, and the consultants can then reference the architectural model in their drawings. They will reference the background into their model and begin to draw their geometry. Structural might show where they are putting foundations or specific framing.
Mechanical might show ducts or air terminals. Plumbing, where they are putting piping. Electrical or switches or lights might be going.
But all of these reference the architectural model file. Then the consultants will reference their model file, which includes the architectural background, into their sheet files. This is also done using xref, and typically it is done by using the reference option and not the overlay option.
In this next slide, you can see the difference between using xref reference and xref overlay. On the left, we can see that there is an architectural model file referenced into an electrical model file that is then referenced into an electrical sheet file. When using the reference option in xref, all model files are carried along from reference to reference in a full visual chain.
On the right, we can see the same workflow with the same drawings, but this time the architectural file was brought in using the overlay option in xref. The electrical model file can fully see and interact with the architectural model file, but once the electrical model file is referenced into the sheet file, the architectural model reference does not come over. The overlay option only carries the link into one drawing.
It does not continue in a reference chain from drawing to drawing. The electrical designer might want to use the overlay option for a number of reasons. Maybe the spacing of the fixtures needed to match the architectural layout, but the architectural layout will be built later, so the builder does not need to see any architectural data on the shop drawings.
It might be confusing, so rather than use the reference option, the overlay option does not include the architectural layers and geometry. Overlay might also be useful if the architectural model is substantially large and bringing it into each consultant sheet would lag the system or make AutoCAD slow. It might need to be referenced to double check model updates, but carrying the link into the sheet file is not necessary, and we always want to be working efficiently without making the computer work too hard.
So as a best practice, if the architect makes a change in their file and that file is shared with the consultant teams, their project files can also be quickly updated, and each team will know that all of the consultant drawings are all referencing the same architectural file. Each consultant might need to update their drawings to reflect the changes from the architectural background, which is why the XRef Compare option is so useful. A consultant could quickly see what changes were made to see if any of their information also needs to be updated.
Using XRef is a best practice workflow, no matter how large the project team might be. Even if you are working on a project by yourself, it is helpful to organize your project into model files and sheet files, and to use XRef to create a network of connected AutoCAD drawings.
