AutoCAD Standards and Best Practices: XREF

[Mark Di Lucido]

I remember Autocad before XREFs—yep we’re talkin’ geezer here. Back then, digital CD production was much less complicated but required much more time to achieve. XREFs were necessitated because Autodesk needed an equivalent to pin bar drafting. Pin bar used one or two mylar layers as the base drawings (XREFs) with a top layer functioning as the host layer, e.g., two bottom mylars might have been road geometry and hardscape with the top mylar drafted as a planting plan.

A question you might have asked is, “under what production circumstances does using XREFs benefit folks the most?” For large projects and/or when several production staff are involved the time investment required (this includes training and making sure all drafters follow standards) is usually worth it. But for smaller projects maybe not. It seems about half of the projects with XREFs I work on are sloppily conceived and implemented. This gets me to how important it is to have easily understood and adoptable standards. Too many or too complicated standards and production staff go rogue. Keep it nimble, easily to understand, and flexible. If not, as soon as you’re out the door they’ll crumble.

XREFs save major time when plan changes are required. And now that clients know we have the magic wand of CAD this is no small thing. My three biggest complaints about XREFs were insertion points (and scale), rotation, and nesting. And, can’t forget forced entity colors in XREFs (again, sloppy drafting) that always made plotting a chore. I usually keep naming straightforward: L-base, L-irrig, L-plant, etc.—it’s intuitive and less to remember.

Last, it’s important to keep in mind that though production of tight CD packages is important, ultimately what we’re selling is design and Autocad & XREFs are just one of several tools that help us get there more efficiently. 

[Sadie Walters]

I am a second year MLA student and XRefs are all the rage in the studio right now.  Professionals, please share!  

[Jason Packenham]

Here’s my two cents on the topic of xrefs…

Attachment or overlay? I generally agree that overlays are the better method. This tends to allow greater control of referencing .dwgs if your project has multiple drawings (i.e. planting.dwg, materials.dwg, etc.). It’s also a nice courtesy if your drawings are being sent to other consultants, as otherwise your drawings would constantly attempt to load attached xrefs when other consultants attempt to work with them.

On the topic of relative vs. absolute paths, I always go with relative paths. As stated in the original post, the issue of network structure can affect absolute paths, but if you manage your project folder setup correctly, this issue can be avoided using relative paths.

All xrefs should be stored in an XREF folder located in the same folder as your .dwgs for the project. Using relative paths, any changes to the network structure won’t affect your .dwgs from searching for this XREFS folder and finding the relevant xref.

[Maria Hines]

As a recent graduate of a 2 year Masters program, construction and technical documents were not something my program focused on. Does anyone have any suggestions, advice, or resources I should look at to become familiar with industry standards?

[Anonymous]

What about just inserting other drawings as blocks at 0,0,0; leaving them alone, and then the team works on different parts of the design on different drawings, copybasing/copyclipping at 0,0,0, and deleting the extra files?

[Author]

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