Custom Revit and Civil 3D plugin development
We turn the tasks your team repeats on every project into buttons inside Revit and Civil 3D. We write them in C# on Autodesk's official API, following your standards, your naming conventions and your deliverable formats. And you own the code.
Free initial diagnosis · No commitment · We reply the same day
In short
A Revit or Civil 3D plugin (also called an add-in) is a program installed inside the software that adds its own buttons to the top toolbar. It is written in C# on Autodesk's official API — the interface that lets code control Revit and Civil 3D — and it automates repetitive, rule-based tasks: quantity takeoffs, sheet production, pipe networks, rebar or quality checks. Zeist builds custom plugins for engineering and construction firms: diagnosis, prototype, development, an installer for the whole office, and support when a new version comes out.
- Typical timeline
- 4 to 8 weeks
- Technology
- C# / .NET · Autodesk API
- Ownership
- You own the code
- Delivery
- Remote · worldwide
If your team deals with any of these, a custom plugin is for you
The same tasks on every project
Takeoffs, sheets, renaming views, exporting drawings. Tasks with no engineering judgment that eat up days of engineering time on every deliverable.
Deadlines that depend on overtime
The design is done, but producing the deliverable takes the whole last week, and any last-minute change puts the date at risk.
Errors that show up in review
Quantities that don't match the drawings, non-standard naming, outdated sheets. The same review comments, project after project.
Dynamo isn't enough anymore
Scripts only one person knows how to run, that break with every version or slow down on large models.
Off-the-shelf tools don't follow your standards
Commercial plugins solve the general case, not your cost codes, your naming or the format your client requires.
Plugins we build for Revit and Civil 3D
Every plugin is built around your office's rules. These are the most common cases:
Quantity takeoffs from the model
Cut and fill volumes, areas by layer, lengths and counts, in your cost-code format and ready for the estimate.
Read the guide: Stop tracking quantity takeoffs in Excel: the guide for engineering firmsAutomated sheet production
Plan and profile, cross sections, title blocks with stationing, revisions and export with the client's naming.
Read the guide: Automated Plan Production in Civil 3D and Revit: Plan and Profile Sheets, Sections and Sheet Sets in MinutesPipe networks and duct banks in 3D
From a 2D polyline to a 3D network with elbows, tees and wyes placed by rule, and duct banks generated from their route.
Read the guide: Civil 3D Pipe Networks: Water, Sewer and Fittings (Elbows, Tees, Wyes) Modeled in 3DRebar modeling and checking in Revit
Automatic rebar from the reinforcement schedule, code checks and rebar takeoffs by bar size, element and level.
Read the guide: Revit Rebar Plugin: Automated Reinforcement Modeling, Code Checking and Bar Bending SchedulesModel version comparison
What changed between the version you had and the one that just arrived: added, deleted, moved and modified, with a report.
Read the guide: How to Compare Two Revit and Civil 3D Models: Automatically Detect What Changed Between VersionsRevit and Excel, both ways
Export, edit parameters in bulk and import them back, with validation first and a log of every change.
Read the guide: Export Revit Schedules to Excel (and Import Them Back): How to Bulk-Edit Parameters Without ErrorsModel audits and quality control
Model health, standards checks and automatic review before every deliverable.
Read the guide: Slow Revit Model: Why It's So Heavy and How to Audit It Automatically Before It Stalls Your TeamHow we build your plugin
- 01
Timeline: 1 week
Diagnosis
We look at the task in your actual workflow, measure how much time it takes and write down the rules the plugin must apply. The initial diagnosis is free.
- 02
Timeline: 1-2 weeks
Prototype
We validate the logic on a real project, in Dynamo or as a minimal version of the plugin. If it doesn't match the manual result, it gets fixed before we move on.
- 03
Timeline: 2-4 weeks
Development
We write the plugin in C# with error handling, a log of what it does and tests on your own models.
- 04
Timeline: A few days
Installation and training
An installer for the whole office, a button on the top toolbar, team training and a user manual.
- 05
Timeline: Ongoing
Support
Adjustments after delivery and updates when Autodesk releases a new version of Revit or Civil 3D.
What your firm gets
- The plugin installed, with its button on the Revit or Civil 3D top toolbar
- An installer to deploy it across the whole office
- The complete source code: the plugin belongs to your firm
- A user manual and training for the team
- Technical documentation so another developer can maintain it
- Tests on your own models before delivery
Custom plugin or off-the-shelf tool
| Criterion | Custom plugin | Off-the-shelf tool |
|---|---|---|
| Follows your standards and naming | Exactly | Only if they match |
| Deliverable format | Your firm's and your client's | The vendor's |
| Your office's rules | Built into the tool | You adapt to it |
| Code ownership | Yours | The vendor's |
| Changes when your process changes | It adapts | Up to the vendor |
| Time to first use | Weeks | Immediate |
Go deeper before you decide
Revit and Civil 3D Add-in Development: The Complete Guide (2026)
The complete guide to Revit and Civil 3D add-in development: what add-ins are, what to automate, C# and the Autodesk API, deployment and cost.
How much does a Revit or Civil 3D add-in cost? 2026 pricing and timeline guide
How much a Revit or Civil 3D add-in costs to build: what drives price and timeline, and how to calculate whether it pays for itself in hours saved.
Dynamo vs C# in Civil 3D and Revit: when to use each + automations that save hours
Dynamo or C# for automating Civil 3D and Revit: the real differences, when each one is worth it, and automations that save hours, with examples.
Automating Revit Tasks: The 12 That Save the Most Time (with Dynamo or a Plugin)
The 12 Revit tasks that save the most hours when automated: sheets, naming, parameters from Excel, batch export and more. With Dynamo or with a plugin.
Civil 3D cross sections: from sample lines to sheets and earthwork volumes, without redoing them on every change
How to create cross sections in Civil 3D: sample lines, section views, section sheets and cut and fill volumes, plus the most common errors and fixes.
Civil 3D to Revit: how to bring surfaces, coordinates, alignments and pipe networks across without anything moving
How to go from Civil 3D to Revit: link or import the surface as a toposolid, share coordinates, and bring alignments, corridors and pipe networks across.
Civil 3D corridors: assemblies, targets, surfaces and intersections, without fighting the model
How a Civil 3D corridor works: alignment, profile and assembly, frequency, targets, corridor surface, intersections and the most common errors.
Revit batch print plugin: export PDF and DWG for every sheet, across every model, without limits
How to batch export Revit sheets to PDF and DWG: what Revit does natively, which plugins exist, and how your own plugin works, with no limits.
Revit revisions and signatures on many sheets at once: a new revision, title block data and signatures in bulk
How to add a revision to many Revit sheets at once, fill title block data in bulk, put signatures on every sheet and sign the PDF.
Revit shared parameters: what they are, how to create them, the .txt file, title blocks and the errors that keep coming back
What Revit shared parameters are, how they differ from family and project parameters, how to create them and use them in schedules, tags and title blocks.
Frequently asked questions
How much does it cost to develop a Revit or Civil 3D plugin?
It depends on scope: how many rules it applies, how many versions of the software it must support and how different the cases it has to handle are. After the diagnosis, which is free, we send a proposal with scope, timeline and cost. The factors that drive the price are explained in our add-in cost guide.
How long does it take to develop a plugin?
Typically 4 to 8 weeks from diagnosis to installation in your office. Small tools, such as a batch rename or a rule-based export, can be ready sooner.
Do we own the plugin's code?
Yes. We deliver the complete source code and technical documentation. The plugin belongs to your firm, and your team or another developer can maintain it.
Which versions of Revit and Civil 3D do you support?
Whichever your office uses. Each Revit and Civil 3D version needs the plugin compiled for it, so we agree at the start which ones are included. When Autodesk releases a new one, the plugin is updated.
Do we need to know how to code to use the plugin?
No. The plugin is a button on the Revit or Civil 3D top toolbar. If you also want your team to be able to modify it, we offer training in the Revit API, the Civil 3D API and Dynamo.
What's the difference between a plugin and a Dynamo script?
Dynamo is ideal for validating an automation quickly. A plugin is better for daily use: anyone on the team can run it, it handles errors, it's fast on large models and it installs across the whole office. We often start in Dynamo and finish with a plugin.
Do you work with companies outside Peru?
Yes. Our team is based in Trujillo, Peru, and works remotely with firms in the US, Europe and Latin America. Peru is on UTC-5 all year, so our working day overlaps with US business hours. Diagnosis, reviews and installation are all done remotely.
Which task would you turn into a button?
Tell us what your team does by hand on every project. In the free diagnosis we measure how much time it takes and tell you whether it calls for a plugin, a Dynamo script or neither.
Let's talk on WhatsAppFree initial diagnosis · No commitment · We reply the same day
Other services
Dynamo automation
Scripts and routines for modeling tasks, parametric geometry, and bulk processing. Fast to validate — ideal while the automation is still evolving.
BIM process audit
We measure where your team's hours actually go and hand you a prioritized plan: what to automate first, with which tool, and how much time you get back.
Courses and mentorship for BIM teams
Hands-on training in the Revit API, the Civil 3D API, and Dynamo — for teams that would rather build and maintain their own tools in-house.