Kerf

Overview

Kerf is a local, open-source CAD workspace for engineers and designers who want to work through either conversational prompts or code. Its unusual breadth makes it relevant to mechanical and electronics design, BIM, jewelry work, simulation, and manufacturing; it is less suited to anyone who expects a ready-made hosted AI assistant.

Key features

Design by prompt or code

Users can describe design changes in plain language, then use the same tool surface through the Python kerf-sdk or JSON-RPC API. That combination is useful for people who want automation and repeatability alongside a conversational workflow. The chat depends on an LLM the user supplies, however, so Kerf does not provide a bundled model or turnkey hosted chat service.

CAD, analysis, and production

Mechanical workflows include a constraint-based sketcher, parametric feature history, validated B-rep geometry, drawings, and persistent face references. Jewelry designers also get ring sizing and stone-setting tools, photorealistic rendering, and manufacturing export. That mix can cover more than shaping a model, but the available tools span many disciplines and may be broader than a focused jewelry or mechanical package needs.

Kerf also includes FEM analysis, topology optimization, SPICE and RF analysis, CAM toolpaths, and G-code output. Listed exports range from STEP, STL, 3MF, IFC4, Gerber, DXF, and G-code to PDF, BOM CSV, Touchstone, GDS-II, and firmware binaries. Its open tool and kernel integrations include JSCAD, OpenCascade, tscircuit, FEniCSx, OpenCAMlib, IfcOpenShell, FreeRouting, and KiCad. This breadth is most compelling for users moving between design and downstream engineering tasks.

Local control and sharing

Kerf runs locally without accounts, and file edits are recorded in local Git history. Its Workshop uses signed, content-addressed objects over an open protocol, without requiring an account or central server; pinned content can be used offline. Those choices favor users who value local records and offline access, though they also put responsibility for the environment and any LLM on the user.

Pricing

Kerf is free: its Free plan costs nothing, is billed Free, and is MIT licensed. It runs locally with no accounts and no billing. There is no cheaper tier to trade features for cost, and no paid hosted plan is offered. The practical trade-off is that chat requires a user-supplied LLM rather than a bundled service.

Platforms

Kerf is listed for API, Linux, macOS, self-hosted, and web use, with a hybrid platform classification. It can be installed from source or Docker, and release archives are provided for macOS arm64, macOS x64, and Linux x64. Source installation requires Python 3.11 or later; its embedded SQLite setup needs no database server. This is a flexible deployment story for technical users, but source installation has a Python version requirement.

Who it's for

Mechanical and electronics engineers, BIM architects, and jewelry designers are among the intended users, as are people in other engineering disciplines. The API and Python tooling also make Kerf a stronger fit for users comfortable scripting their workflows. Jewelry designers looking for ring sizing, stone setting, rendering, and manufacturing export can use the same workspace as those handling broader engineering tasks.

Pros and cons

Pros

• Wide engineering scope: CAD, simulation, analysis, and manufacturing tools sit in one workspace, which can suit cross-discipline projects.
• Scriptable workflows: Python and JSON-RPC provide a route beyond chat for repeatable or automated design changes.
• Local-first operation: Local Git history, no-account operation, and offline use of pinned Workshop content support users who want to keep work under local control.
• Free and open source: The MIT-licensed Free plan has no billing, and includes the listed modeling, jewelry, and manufacturing capabilities.

Cons

• Chat needs an external LLM: Users must supply the model, so chat is not a complete out-of-the-box service.
• Technical setup can be part of the job: Source installation requires Python 3.11 or later, and Docker or source installation may be a better fit for technically capable users.
• Broad scope may be unnecessary: Users who only need a narrow design workflow may not benefit from its wide set of engineering tools.

Alternatives

For a broader jewelry-software shortlist, start with Jewelry Design Software.

Choose Rhino 3D if you want a paid Windows or macOS option with a permanent Commercial license for one concurrent user; it also has a free plan and trial. Pencil may fit a browser-based jewelry workflow: its free plan limits users to three designs and no AI credits, while Professional costs $39 a month and includes 200 AI credits. For a sculpting alternative, ZBrush has a free iPad plan with 28 brushes and a subscription option with price not listed.

Autodesk Fusion is worth considering for integrated CAD/CAM, team collaboration, PCB design, and electromechanical integration; its plan costs $57 a month, billed annually. Diatech Studio is another freemium web option. CounterSketch is a paid Windows and macOS membership at $349 a year, with tech support, an online academy, and library updates. Drakon sells Copilot credits in one-time packages, including 5,000 for 20.00 EUR and 12,500 for 50.00 EUR. Jewelry CAD Dream is a paid Windows option with no free plan or trial.

Verdict

Kerf is a strong fit for technically minded engineers and jewelry designers who want a free, local workspace that connects modeling with analysis and manufacturing, especially if they value scripting and local history. Its breadth and lack of billing are persuasive; look elsewhere if you need chat with a bundled model or prefer a more narrowly focused, fully hosted workflow.