CAD Plug In Developer

Trilon is building a digital platform that gives engineers one place to manage, share and reuse their design data. The desktop tools our engineers use every day, Autodesk Civil 3D, the Bentley OpenX family (OpenRoads, OpenRail, OpenSite, OpenComms) and Esri ArcGIS Pro, need to connect to that platform directly.

As our Senior CAD Plugin Developer, you will own those connections. You will design and build the plugins that let an engineer export a design from their CAD tool into the platform, bring designs back by project, and keep spatial data in sync with ArcGIS. You will set the technical direction for our plugin work and be the team’s expert on CAD and GIS APIs and civil design data.

The hard part of this job is less the CAD APIs and more how designers actually work: when they save, what they reuse, where a plan set comes from, and what they will tolerate inside a design session. You will spend real time with civil designers so the plugins fit their workflow instead of interrupting it.

Key Responsibilities

• Build the plugins. Design, build and ship production plugins for AutoCAD / Civil 3D (.NET, ObjectARX) and MicroStation / OpenX Designer SDKs (.NET and native SDKs).
• Own the export path. Build the end-to-end flow from a click in the plugin to the platform: sign-in through the platform (OAuth 2.0 / OpenID Connect from a desktop app, with tokens that persist between sessions), packaging the design, upload through platform APIs, and handling partial failures and retries.
• Build the import path. Let users browse designs by project, pick files and download them into the CAD session through secure, time-limited download links.
• Get the data right. Extract and convert civil objects (alignments, profiles, corridors, surfaces, pipe networks, feature lines) and their coordinate systems into open formats such as LandXML, IFC and GeoJSON, without losing data.
• Connect to GIS. Build ArcGIS Pro add-ins and integrations that sync CAD spatial data with ArcGIS, including styles, spatial reference files and OGC-standard services.
• Fit the designer’s workflow. Sit with civil designers, watch how they work in a session, and shape when and how the plugin asks for their attention. Validate output against real projects before it ships.
• Instrument what you ship. Add usage and error events to the plugins so we can see how export and import perform in the field.
• Package and support. Own installers, code signing, versioning across yearly Autodesk and Bentley releases, and deployment to engineers’ machines.
• Partner with platform engineers. Work with the platform team on the REST and GraphQL APIs and the storage the plugins call, and on any third-party service integrations the plugins depend on.
• Lead technically. Set plugin architecture and coding standards, review code, and mentor other developers on CAD and GIS APIs.

Skills, Knowledge and Expertise

• 6+ years of professional software development, with at least 4 years building and shipping CAD plugins or extensions used in production.
• Strong C# and .NET, and working C/C++ for native CAD APIs.
• Deep experience with the AutoCAD and Civil 3D APIs; hands-on experience with the MicroStation SDK or one or more of the Bentley OpenX Designer SDKs (OpenRoads, OpenRail, OpenSite, OpenComms).
• Working knowledge of civil design workflows and processes: how roadway, drainage, grading or site designers move from survey to model to plan set, what they reuse across projects, and where the time goes.
• Experience calling REST and GraphQL APIs from desktop applications, including OAuth 2.0 / OpenID Connect sign-in and secure token storage.
• Experience with coordinate systems, map projections and spatial data formats (LandXML, GeoJSON, shapefiles, geodatabases).
• ArcGIS Pro SDK, ArcGIS REST APIs, Arcade, or QGIS development.
• PostgreSQL / PostGIS or other spatial databases.

About Trilon

Trilon was formed with the vision of building the next Top 20 infrastructure consulting firm in North America by bringing together some of the nation’s best infrastructure consulting firms, focused on delivering practical and sustainable infrastructure solutions. Trilon is backed by Alpine Investors, a PeopleFirst Private Equity Firm. Trilon currently comprises 5,500+ staff across the US. For more information, visit www.trilon.com.

Pay Transparency

The base salary range for this role is indicated in the posting. This range reflects the company’s good faith estimate of the compensation for this position at the time of posting. Final compensation will be determined based on factors such as experience, skills, qualifications, internal equity, and geographic location.