CAD Plug In Developer

Trilon Group

. Design, build and ship production plugins for AutoCAD / Civil 3D using .NET and ObjectARX, and for MicroStation / OpenX Designer using .NET and native SDKs.

Posted 10/20/2026full-timeRemote • United StatesMid-LevelSenior💰 $120,000 - $185,000 per yearWebsite

Core Competencies

Role fit

Core Competencies

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Demonstrates expertise in developing and shipping CAD plugins using C# and .NET, with a strong understanding of civil design workflows and integration with spatial data systems. Proficient in collaborating with engineers on API integrations and ensuring high-quality plugin performance through instrumentation and user feedback.

Highest-signal resume keywords

C# DevelopmentCAD Plugin DevelopmentAutoCAD API ExperienceMicroStation SDK ProficiencyREST and GraphQL API Integration

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills

C#C/C++.NETAutoCAD APICivil 3D APIMicroStation SDKArcGIS Pro SDKOAuth 2.0LandXMLGeoJSON

Soft Skills

CollaborationMentoringProblem-Solving

Tools & Technologies

PostgreSQLPostGISArcGIS REST APIsOpenX Designer SDKs

Industry Keywords

Civil Design WorkflowsSpatial Data FormatsCoordinate SystemsMap Projections

Tech Stack

Tools & technologies

GraphQLPostGISPostgresC++.NET

About the role

Key responsibilities & impact

Design, build and ship production plugins for AutoCAD / Civil 3D using .NET and ObjectARX, and for MicroStation / OpenX Designer using .NET and native SDKs.
Build end-to-end export flows from desktop plugin sign-in through platform upload, including OAuth 2.0 / OpenID Connect, token persistence, packaging, partial-failure handling and retries.
Build import flows that let users browse designs by project, select files and download them into CAD sessions through secure, time-limited links.
Extract and convert civil objects such as alignments, profiles, corridors, surfaces, pipe networks and feature lines into LandXML, IFC and GeoJSON while preserving data.
Build ArcGIS Pro add-ins and integrations that synchronize CAD spatial data with ArcGIS, including styles, spatial reference files and OGC-standard services.
Observe civil designers’ workflows and shape plugin interactions around their needs; validate output against real projects.
Add usage and error instrumentation to plugins.
Own installers, code signing, versioning across Autodesk and Bentley releases, and deployment to engineers’ machines.
Collaborate with platform engineers on REST and GraphQL APIs, storage and third-party service integrations.
Set plugin architecture and coding standards, review code and mentor developers on CAD and GIS APIs.

Requirements

What you’ll need

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, including roadway, drainage, grading or site design workflows.
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.

Benefits

Comp & perks

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.