Popkern

Popkern is a free open-source parametric BRep CAD kernel written in Rust that builds solid parts with code.

Popkern is a free, open-source parametric boundary-representation geometry engine for solid computer-aided design written in Rust. It lets users build complex parts using short Rhai scripts, backed by research-class CAGD algorithms. Parts can be developed as single scripts or as multi-step projects using numbered migration scripts with a history scrubber. The software supports booleans, fillets and chamfers with smooth corners, sweeps, revolves, lofts, shelling, constrained sketches, and STEP file import and export. It is designed for engineers and makers who want to create solid models through code and command line tools.

Popkern at a glance

Best for: Software engineer
Runs on: Web, CLI, open source
Pricing: Free forever
Released: October 2026
Category: AI coding tool
Website: popkern.dev

Key features

Parametric boundary-representation geometry engine
Interactive script editing in the browser
Booleans, fillets, and chamfers with smooth corners
Sweeps, revolves, and lofts
Shelling and sketches with constraints
STEP file import and export
Command line interface for builds and conversions

Use it for

Building solid CAD parts with Rhai scripts
Exporting models to STEP files via the command line
Managing part history with database-like migration scripts

Alternatives to Popkern

SolidCraft — It runs on the desktop, in the browser, via CLI, and through an MCP server.
Hackerscad — Combines code-based modeling with direct mouse editing and an AI agent MCP server.
SolveCraft — A command-driven architecture supports scripting, headless CLI use, and AI agents.
Cad Studio — Generates parametric build123d models and ISO drawings through an integrated coding agent.
Lobole — Drives the GUI, Python scripts, and AI agents through a single unified command layer.
jevgrep — Reduces coding agent costs by providing targeted, relevant repository context.
TextoCAD — Generates editable parametric CAD code with named dimensions instead of static meshes.
ModLens — Converts screenshots and charts into structured JSON data for coding agents.
Saerskriven — Keeps your threat model directly with your code.
Neptune — It combines a fast native terminal engine with built-in management for AI coding agents.
Popcraft — Connects AI agents to media generation tools via a single OAuth sign-in without API keys.
OpenCode — Works with 75+ model providers, local models, and existing subscriptions

All Popkern alternatives