While AutoCAD dominates UK construction and building services projects, MicroStation remains the preferred CAD platform for many large-scale infrastructure, rail, highways, water and process plant projects. If you're working on one of these projects, you'll often receive design drawings in DGN format rather than DWG, and any redline markups from site will need to be incorporated back into MicroStation rather than AutoCAD.
Understanding how redline incorporation works in MicroStation environments is essential for subcontractors, EPC firms and specialists who may not use the platform day-to-day but still need to deliver accurate, updated design information during construction and at handover.
Why MicroStation Is Used on UK Infrastructure and Process Projects
MicroStation is developed by Bentley Systems and is widely specified on projects governed by organisations such as Network Rail, National Highways, water utilities and major oil and gas operators. These clients often mandate MicroStation as part of their CAD standards, and require all design consultants and contractors to comply.
The platform is preferred for its ability to handle very large, complex datasets such as civil alignments, utility corridors and plant layouts. It also integrates tightly with other Bentley products used for infrastructure design, including OpenRoads, OpenPlant and OpenBuildings.
For contractors more familiar with AutoCAD, this can present a challenge. You may receive issued-for-construction drawings in DGN format, mark them up on site in the usual way, but then struggle to find someone who can competently incorporate those changes back into the native MicroStation files.
How Redline Markups Are Collected on MicroStation Projects
The process of collecting redlines is largely the same regardless of the CAD platform used for design. Site engineers, supervisors and installation teams mark up printed or PDF drawings to show deviations, as-installed positions, dimension corrections and design queries.
These markups may be made using red pen on paper prints, or digitally using tablets and annotation software such as Bluebeam, PDF Expert or similar. The key is that the information is captured clearly enough to be interpreted and modelled accurately by a CAD technician.
On MicroStation projects, it's important that redlines reference the correct drawing issue, sheet number and revision. Because DGN files can contain multiple models and references within a single file, clarity around which view or model is being marked up becomes even more important.
Incorporating Redlines into MicroStation DGN Files
Once redline markups have been collected, they need to be incorporated into the native MicroStation design files. This is not simply a case of overlaying a scanned image. It requires a skilled technician to interpret the markup, edit the geometry, update dimensions, adjust references and ensure the file remains compliant with the project's CAD standards.
Common tasks include moving pipes, ducts or cable routes to reflect as-installed positions, updating equipment tag references, adjusting civil levels or alignment data, and adding new elements that were installed but not shown on the original design.
Just as with redline markup incorporation in AutoCAD, the output must be accurate, layered correctly, and ready for onward use in coordination, clash detection or record drawing production.
Challenges Unique to MicroStation Workflows
One of the main challenges is that MicroStation uses a different file structure and referencing system to AutoCAD. Drawings are often constructed from multiple referenced DGN files, and changes in one file can affect several sheets. Technicians must understand how these references work to avoid breaking links or causing unintended changes elsewhere in the drawing set.
Another challenge is font mapping and line style definitions. MicroStation uses resource files for these, and if they are not set up correctly, text and linework may display incorrectly when files are opened or exchanged. This is particularly important when producing final record drawings that will be archived or issued to the client's asset management system.
Version compatibility can also be an issue. MicroStation has evolved through several versions, and older DGN files may not open correctly in newer releases without migration. Contractors need to confirm which version of MicroStation the project is using and ensure their CAD partner can work in that environment.
Converting Between AutoCAD and MicroStation
In some cases, subcontractors or specialist designers may produce their own drawings in AutoCAD, which then need to be converted to MicroStation DGN format for inclusion in the main design package. While both platforms support import and export between DWG and DGN, the conversion is rarely perfect.
Line styles, hatches, text styles and blocks do not always translate directly. Custom linetypes in AutoCAD may appear as solid lines in MicroStation unless manually remapped. Similarly, AutoCAD blocks may need to be converted into MicroStation cells, and layer structures often require reorganisation to match the project's CAD manual.
For this reason, it's usually more reliable to have the conversion and cleanup handled by someone experienced in both platforms, rather than assuming a simple file export will suffice.
Producing As-Built Drawings in MicroStation
At the end of a project, contractors are typically required to provide as-built and record drawings that reflect the completed installation. On MicroStation projects, these must be delivered in DGN format, often with specific title blocks, naming conventions and metadata as defined by the client.
As-built production involves consolidating all site redlines, design changes, RFIs and approved variations into a final, coordinated set of drawings. This must be done in the native MicroStation environment to ensure compatibility with the client's document control and asset management systems.
Many contractors do not have in-house MicroStation capability, particularly smaller M&E or civils subcontractors. In these cases, outsourcing the as-built drawing production to a specialist provider ensures the deliverable is correct, on time, and compliant with project requirements.
Outsourcing MicroStation Redline and As-Built Work
Outsource CAD supports clients working on MicroStation-based projects across rail, highways, water, power and oil and gas sectors. We incorporate redline markups into DGN files, produce as-built drawings to client CAD standards, and handle file conversion and coordination between AutoCAD and MicroStation where required.
Our team works in the version of MicroStation specified by your project, whether that's CONNECT Edition, V8i or an earlier release. We follow your CAD manual, apply the correct reference files and resource definitions, and deliver drawings ready for submission or upload to your project's common data environment.
This is particularly useful for contractors who win work on infrastructure projects but don't want to invest in MicroStation licences and training for what may be a one-off requirement. It also helps during peak periods when your design team is stretched and you need reliable overflow support that understands both the technical and administrative side of the task.
What You Need to Provide
To incorporate redlines into MicroStation drawings, we typically need the original issued-for-construction DGN files, the redline markups in PDF or scanned format, and a copy of the project CAD manual or specification. If custom fonts, line styles or cell libraries are used, these should also be provided.
Clear communication about which drawing references are live, and whether any seed files or templates must be used, helps avoid rework. If the project uses a particular revision numbering or file naming system, let us know at the outset so everything is set up correctly from the start.
Turnaround depends on the volume and complexity of markups, but most redline updates are completed within 24 to 48 hours. Larger as-built packages or full drawing set updates are scheduled based on your programme and submission deadlines.
If your project requires MicroStation-based redline incorporation, as-built drawing production or file conversion support, get in touch with our team at info@outsourcecad.com or call +44 28 9009 8876.
