Author: Kate Ming AutoCAD Civil 3D, AutoCAD

Over the past year, through Ideate, I have been training Civil 3D to Caltrans employees. Recently, it got me thinking back to my design days as an Inroads master. Now that I have as much experience with Civil 3D as Inroads, I’d like to illuminate for you some high level difference between these two competing software, specifically integration with the CAD platform and data management.
At a glance, Inroads and Civil 3D are seemingly the same software. They both create civil design objects such as roads, utilities, surfaces, etc. I am not going to get into the ins and outs of what they offer. What is more interesting is the difference in their architecture. They are both vertical design software built on a CAD platform. Inroads works with Microstation while Civil 3D works with AutoCAD. Civil 3D is seamlessly built into the AutoCAD interface while Inroads is a separate window. 

This highlights the first main difference: integration with the CAD platform. Civil 3D’s integration into the user interface makes transitioning from AutoCAD to Civil 3D easy. All of the Civil 3D commands are placed amongst the AutoCAD commands. Civil 3D objects can be edited using the common AutoCAD commands. Inroads, however, feels like a separate software from Microstation. All of Inroads functions are contained on the Inroads window, which is separate from Microstation. You need to open Microstation and Inroads in order to work with Inroads. In order to edit an Inroads entity, you need to use Inroads commands. Essentially, all of Inroads data is contained in one of the many Inroads files, which are separate from the CAD file that you may be using. This is why you can’t edit Inroads objects using Microstation.

This leads me to another main difference: data management. In Civil 3D, the drawing itself is a database which contains all of the Civil 3D objects. This allows the software to be dynamic. Of course, you are not going to want all of your data in one drawing, even if it’s possible. That would create a huge and slow file that could crash the software. You can create separate design files instead of having everything in one file and share that data. Civil 3D objects are shared amongst drawings through Data Shortcuts. Data Shortcuts are XML files that act as a pointer to the file that has the needed data. It in a sense creates a path to data from another drawing for purposes of displaying.

Conversely, data for Inroads is contained in multiple files. Each data-type has its own file, i.e. surfaces and alignments both have a separate file types that are loaded into Inroads. Both of these files are separate from the Microstation dgn file. In order to display any of this data in the dgn file, you need to have a preference file loaded. So at any given time, you need to have a minimum of 3 files open to work: the object file (an alignment for example), a preference file, and the microstation dgn file. That’s a lot of files to keep track of. You can create a project file that will open all relevant files when you want to work on a project. Having a lot of different files makes the software inherently less dynamic. For example, if you update a surface, you will then have to open the alignment file that may be affected by the surface, and then update the alignment file. All of these separate files can make data management difficult. 

To sum it up, Civil 3D is more dynamic then Inroads due to all Civil 3D data being in the drawing. This is definitely a plus for Civil 3D, despite the fact that it can lead to large files that can crash. The solution to this is to create multiple files and share data using the data shortcuts. Civil 3D also is integrated well with the AutoCAD interface and commands, which makes moving from AutoCAD to Civil 3D easy. Another plus to Civil 3D is its integration with other Autodesk products.

Inroads is less dynamic and it is harder to learn to use because it is not integrated with Microstation. It is a separate software that works on top of Microstation. Sharing data, however, is easy because it is contained are separate files. There is no need for a data sharing system, like Civil 3D’s data shortcuts.

Is one better? I don’t think so. They are different. It depends on what your clients and colleagues are requesting and what other software you are working with. Additionally, it depends on how you like to work. If you have never used Inroads or Civil 3D, I hope this opened your eyes to some of the key differences.

Thank you for reading. For more information on the software solutions, training and consulting Ideate provides, please visit the Ideate Inc. homepage.
         Kate Ming
Kate Ming
AEC Application Specialist

Kate is a California licensed civil engineer with a BS in Civil and Environmental Engineering from UC Berkeley. Prior to Ideate, she worked at a multinational company for four years doing general civil design on large infrastructure projects. She is versed in roadway, rail, utility design and site development. She also has experience with utility demand analysis and Low Impact Development plans. As a Civil 3D Autodesk Certified Professional Kate provides training and support for Civil 3D, AutoCAD, and InfraWorks.