I’m looking for an experienced C++ developer with strong ObjectARX knowledge to enhance and maintain custom 3D modeling tools inside AutoCAD. The work is focused on improving existing functionality rather than building everything from scratch. Scope of work includes: Improving and extending custom 3D modeling features inside AutoCAD. Debugging and fixing issues in an existing AMEAPI-based codebase that currently runs in AutoCAD 2022. Updating face-selection functionality (ap_sel_face or similar) so it works reliably with shaded 3D solids, with proper cursor/face feedback. Ensuring compatibility and smooth behavior in modern AutoCAD environments, and preparing the code for future updates if needed. Requirements: Strong experience with C++ and Visual C++. Proven ObjectARX / AutoCAD plugin development experience (please share examples). Solid understanding of 3D geometry and CAD concepts. Ability to read, understand, and refactor existing code. Nice to have: Experience with ProgeCAD or similar AutoCAD-compatible platforms. Familiarity with AMEAPI or legacy AutoCAD 3D APIs. Project details: Engagement: Less than 30 hours per week to start. Duration: 1–3 months, with potential extension based on results. Please include in your bid: a brief summary of your ObjectARX experience, examples of similar AutoCAD/CAD tools you’ve built, and your availability (hours per week, time zone).