CAD Skills vs Relay: Features, Pricing & Which Is Better (2026)
A side-by-side comparison of CAD Skills and Relay — features, pricing, and ideal use cases — to help you decide which AI tool fits your workflow.
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CAD Skills
earthtojake
Open-source library of agent skills for CAD, robotics, fabrication, and simulation — generate STEP/STL, URDF/SRDF/SDF, DXF, and slicer G-code from prompts.
Key features
- Prompt-to-CAD Generation: The CAD skill creates and edits parametric CAD models from natural language or image requests, exporting to STEP, STL, 3MF, and GLB.
- URDF Robot Description: Writes robot structure files with links, joints, limits, inertials, and meshes ready for ROS-based stacks.
- SRDF for MoveIt2: Adds planning groups, end effectors, named poses, and collision rules on top of a URDF for MoveIt2 planning.
- SDF Simulation Worlds: Creates simulator models and worlds with frames, physics, sensors, and lights.
- 2D DXF Drawings: Produces cut-ready DXF profiles, templates, gaskets, and layouts from Python or CAD geometry.
- G-code Slicing: Slices supported mesh files into validated, printer-profiled FDM G-code using real slicer CLIs.
- Bambu Lab Print Jobs: Dry runs, uploads, and cautiously starts local Bambu Lab prints from validated G-code.
- CAD Viewer Previews: Local browser previews for CAD, G-code, URDF, and other robot files for fast agent iteration.
Best for
- Agentic Mechanical Design: Let a coding agent iterate on brackets, flanges, and enclosures directly from natural-language specs.
- Robot Description Authoring: Generate URDF/SRDF/SDF files for new robot arms or mobile bases without hand-writing XML.
- Rapid Prototyping: Take a CAD model to sliced, printer-ready G-code and kick off a Bambu Lab print from within an agent workflow.
- Custom Part Fabrication: Produce DXF/STEP files pre-checked for SendCutSend, then order laser-cut or CNC parts.
- Simulation Setup: Author SDF worlds for physics simulators with the right frames, sensors, and lighting for robotics research.
- Off-the-Shelf Sourcing: Use step.parts to pull ready-made STEP models for common hardware like screws, bearings, and connectors.
R
Relay
Relay
AI phone receptionist that builds itself from a business's website to answer every call and book, reschedule, or cancel appointments 24/7.
Key features
- One-Click Build: Paste a website and Relay drafts the agent profile, knowledge base, prompt, and call wiring in about 38 seconds.
- 24/7 Call Answering: Picks up every call day or night in the caller's local time, with no voicemail or hold music.
- Real Calendar Booking: Checks live availability and writes appointments, reschedules, and cancellations directly to the business's existing booking system.
- Booking Integrations: Connects to 7+ systems including Google Calendar, Square, Calendly, Outlook, Housecall Pro, Workiz, and Vagaro with one sign-in.
- Grounded Answers: Answers caller questions from the business's own facts and knowledge base rather than guessing.
- No-Config Setup: Requires no dashboards, prompt engineering, or manual call-flow building.
Best for
- Missed-Call Recovery: Capture bookings from calls that would otherwise ring out when staff are busy or closed.
- Appointment-Based Businesses: Let salons, clinics, and home-service providers automate booking, rescheduling, and cancellations by phone.
- After-Hours Coverage: Answer and book calls 24/7 without hiring overnight reception staff.
- Fast Agent Deployment: Stand up a working phone agent from a website link without engineering time.
- FAQ Handling: Answer common caller questions about hours, services, and pricing from the business's own information.