Should we rename this post Civil 3D Reference Templates are Derived and Dependent? My use of classic Latin references does sometimes gets in the way. However, the Latin verb redux combines well the concepts of both derived and dependent. In the case of Style references in Autodesk Civil 3D, the combined implication seems most apt.
A TREF is a Template Reference
We’re here to answer questions about Civil 3D TREFs. First off. What’s that?
A Reference Templates (TREF) is a collection of AutoCAD Styles (Layers, Blocks, TextStyle, etc), Civil 3D and AutoCAD Settings, and Civil 3D Styles from one or more outside resource dwg(s) or dwt(s) file that is used in the Civil 3D Reference Template Tool stack to make those vital resources for Civil 3D external to the current drawing.
No great mystery here.
A TREF is sort of like an XREF for the above dependent and derived Civil 3D and AutoCAD Styles and Settings.
The implementation of TREFs in our Civil 3D projects improves adherence to CAD Standards.
TREFs provide a method to create and maintain more adaptive Civil 3D production environments for us to work in. By changing and updating the TREF(s) in our project drawings we can update and change our Standards to meet the diverse demands of our clients.
The latest and greatest Framework for Civil 3D 2025 Release 8 products ship with functional example TREF based Civil 3D Templates in both STB and CTB. That even includes our most affordable Templates Only trial product.
The Jump Kit product ships with multiple example Civil 3D Sandbox projects that employ a basic single file TREF implementations.
See the recent The New Civil 3D 2025 Framework Products post.
Framework customers get a Civil 3D that works out of the box? Imagine that.
Basic TREF Implementation in a Project Drawing
Note the good news that the fundamentals, mechanics, and principles of Civil 3D TREF implementations haven’t changed much since way back in Civil 3D 2020.
The real question is, “Do we employ them?”
Because we employ the simple approach shown in the video, we did not, and do not, expect Civil 3D Users to manage all the nuances and more arcane mechanics of the Reference Tool’s Settings dialog boxes.
Single File Reference Template Rules
Best not to trust the functional results of even a single-file TREF implementation in releases of Civil 3D before the Civil 3D 2019.2+ release. So, if you tried Reference Templates back in the day and were disappointed, I strongly encourage you to try again.
- We cannot employ the template we started a project drawing from as the single-file Reference Template.
No circular references allowed.
We all know about that self-referencing thing with XREFs and DREFs. - We can use the same TREF Template with a different name and probably, for sanity’s sake, a different path location.
- No release of Civil 3D supports relative paths in the Reference Template Tool resources.
In practice that means if we must relocate our Civil 3D project drawings, we must adjust the stored file paths. - We get to choose thoughtfully whether to locate the TREF references inside the project or in a shared resource location on the local computer, the network, or the Cloud.
- To upgrade project drawings faster we can employ the classic Insert/Explode method to push the existing drawings into a new Reference Template Target with the new single-file TREF attached.
- We can use the Civil 3D Batch Save Utility with crafted scripts and lisp to do the whole, or parts, of a project.
No sweat to employ Batch Save except the obvious need to test our scripts ad nausea.
A TREF Civil 3D Wish List Tool
An external TREF name and path editor for our Civil 3D projects is high on my Civil 3D Wish List.
Thankfully, the Reference Explorer tool in the Autodesk Desktop Connector (ADC) does report on drawing TREFs.
The ADC's Reference Explorer is the fastest way to check for broken TREFs without opening a drawing. Good stuff.
See the Civil 3D Reference Replacement and Tools post for an in-depth video and post review.
A TREF is a Target Reference
We can get immediate improved production results even from simple TREFs without undue effort or major training and implementation efforts. Over time a continuously improved collection of edited and refined, project-based TREF resource template targets should produce better and more task specific template target collections.
The Civil 3D Reference Template Tool and TREFs don’t solve all our Civil 3D Style Management problems. Where we build, edit, and store the known good remains a challenge. The Civil 3D TREF tech simply allows us to manage easier the end results.
A new start root TREF Template seems to be a trip back to a simpler time.
Refence Template Construction in Civil 3D
The fundamentals and principles of Civil 3D TREF construction haven’t changed much since Civil 3D 2020. Civil 3D 2022+ releases seem to produce consistent results with modifications to the internal Reference Template Tool Settings.
During TREF Construction:
- The TREF construction process, like all template creation processes in Civil 3D, is additive.
In other words, we want to always add to the resource and try to avoid both AutoCAD and Civil 3D Purge(s) all together if possible. - Cover the AutoCAD Style dependencies first.
This means Layer systems, Block definitions, Dimstyles, Textstyles, etc.
Remember that TREFs still will not load Layer States. - We need separate resource libraries to store the known good resources we add to our new TREF Template resources.
- Remember to reset (Purge) the Civil 3D Style, Label Style Defaults, and Civil 3D command Settings with templates (or drawings) created and maintained for that purpose.
The Framework for Civil 3D products ship with NoStyles templates for this reason. - Both the classic Insert/Explode and the newer AutoCAD Block palette tool methods work well to add both AutoCAD and Civil 3D Style resource content to a TREF.
- When we employ multiple resource drawings in the Reference Template stack it is generally a good idea to confine and separate our changes to the different Settings tab properties.
One resource adds Layers and Blocks, another Property Set resources, and yet another the Civil 3D Style library resources.
We want to especially avoid Reference Template Tool Settings property conflicts. - Recent releases of Civil 3D do appear to support nested TREFs.
That means we can reference a resource drawing that itself contains a TREF.
The support for a nesting capability allows us to separate, edit, and better manage chains of standards more effectively.
Register on the website to access our in-depth Documentation and Help resources and videos on Civil 3D Templates and Reference Templates.
TREF Usage Realities
All Civil 3D Users must understand how to check the current loaded TREF template(s) and should understand where our TREF resources (our known good resources) come from.
Practically, we should probably avoid TREF implementations that require Civil 3D Users to make manual and/or detailed changes in the Reference Template Tool’s Settings tabs.
Reference Templates are a powerful and useful management tool for Autodesk Civil 3D. To not employ a Reference Template these days, simply costs us time, energy, and money.
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