The Weekend Mental Model

CAD automation and AI in CAD for design engineers: 3 hours this weekend to understand it, 3 days to let it sink in.

Don't build anything this weekend. Just build a mental model.

About 3 hours over the weekend, then 5 minutes a day for three days. By Thursday you will know what CAD automation is, who uses it, what they build, how AI fits in, and whether you want to learn it.

Your weekend plan

When	Time	What to do
Saturday morning	1 hour	Understand CAD automation: what it is, which industries use it, what they build
Saturday afternoon	1 hour	Ask an AI four questions, then the follow-ups
Sunday morning	45 minutes	AI in CAD: copilots, projects you can build, topics to learn
Sunday afternoon	30 minutes	How to prepare, how to learn, and search for resources
Monday to Wednesday	5 minutes a day	Write one sentence a day and let it sink in
Thursday	10 minutes	Check if you are ready to start

Saturday morning · 1 hour: understand CAD automation

What CAD automation is

Every CAD program you use has an API: the same software, controlled by code instead of clicks. CAD automation means writing programs that drive that API to create, check, export, or update models and drawings.

Language	Where it is used
C#	Main language for SolidWorks, Inventor, AutoCAD, Revit, and Tekla add-ins (COM and .NET APIs)
VBA	Quick macros inside SolidWorks and Inventor. Fine to start, limited for team tools
Python	AI work, plus CAD tools with native Python such as Fusion, FreeCAD, Rhino, and Blender

Mental model: every button you click is a function you can call.

It is much more than repetitive tasks. Batch export is level 1. The real value is rule-driven systems: configurators, design rules, drawing checks, CAD connected to ERP and PLM, and CAD running on servers behind web apps.

Industries using CAD automation

Industry	Typical CAD platforms	What they automate
Industrial machinery and special purpose machines	SolidWorks, Inventor	Configurable frames and conveyors, drawing packs, BOM export to ERP
Automotive and tier suppliers	CATIA, NX, Creo	Fixture and jig design, standard part libraries, drawing checks, PLM data
Aerospace	CATIA, NX	Knowledge-based engineering (KBE), standards compliance, traceability
Pumps, valves, HVAC, enclosures (configure to order)	SolidWorks, Inventor	Product configurators, quoting (CPQ), sales drawings in minutes
Sheet metal fabrication	SolidWorks, Inventor, Solid Edge	Flat patterns, DXF export for laser cutting, part numbering
Architecture and construction (AEC/BIM)	Revit, Tekla, Civil 3D	Sheet creation, clash detection, quantities, rebar and steel detailing
Plant and process	AutoCAD Plant 3D	Piping isometrics, spec checks, line lists
Engineering services companies	All of the above	Add-ins, configurators, and data migration for global OEM clients

Real CAD automation projects

Batch export: every drawing in a folder to PDF, DXF, and STEP with clean file names.
Property and title block automation: fill and validate custom properties across thousands of files.
Drawing QA checker: flag missing properties, wrong revision format, outdated templates before release.
BOM to ERP: push assemblies and properties into SAP or another ERP without retyping.
Product configurator: pick options in a form, get a valid model, drawing, and BOM.
Design rules (KBE): sizes, holes, and clearances driven by engineering rules, not memory.
PDM and PLM integration: check-in rules, lifecycle states, automatic notifications.
Data migration: move legacy files between CAD versions or platforms in bulk.
CAD on the web: headless CAD on a server, a 3D viewer in the browser, quotes for customers.

Notice the pattern: every project is a rule your team already follows, written as code.

Saturday afternoon · 1 hour: ask an AI four questions

Copy each prompt into ChatGPT, Claude, or Gemini. Read the answer, then ask the follow-ups. Use the "A good answer mentions" list to judge the answer, and push back if it is vague.

1. What is a CAD API?

Copy this prompt

Explain what a CAD API is to a design engineer who uses SolidWorks every day but has never written code. Use one example from drawing release.

Then ask

Show me 10 lines of C# that print every custom property of the active SolidWorks part, and explain each line in plain English.
What does the SolidWorks macro recorder do, and what are its limits?

A good answer mentions

The API is the same software you use every day, controlled by code instead of clicks.
An object model: the application, then the document, then features, dimensions, properties, drawing views.
Real function names, for example OpenDoc6 or CustomPropertyManager.
The macro recorder as a way to see which calls your clicks turn into.

Mental model: Every button you click is a function you can call.

2. Which programming language do I need?

Copy this prompt

Which programming language should I learn first for SolidWorks, Inventor, AutoCAD, or Revit automation? Compare C#, VBA, and Python in a table: what each is used for, pros, cons.

Then ask

What is the difference between a macro and an add-in?
Which C# basics do I need before I touch the SolidWorks API?

A good answer mentions

Most desktop CAD APIs are built on COM and .NET, so C# is the main language for add-ins.
VBA is fine for quick macros but limited for tools a team will use.
Python is the main language for AI work, and some CAD tools (Fusion, FreeCAD, Rhino) support it directly.
A clear first pick for your CAD platform, not "it depends" with no answer.

Mental model: C# talks to CAD. Python talks to AI.

3. How can AI connect to CAD?

Copy this prompt

How can an AI model like ChatGPT or Claude actually control CAD software? Walk me through the chain from my prompt, to an API call, to a changed model, with one example.

Then ask

What is tool calling (function calling)? Explain it with a CAD example.
What is an MCP server, and how could it expose SolidWorks functions to an AI model?

A good answer mentions

The model cannot click. It asks for a tool, and your code runs the CAD API call.
Tool calling or function calling, and MCP servers as a standard way to expose tools.
Validation and human approval before anything changes a model or drawing.
Text-to-CAD by generating code (for example CadQuery) as a separate approach.

Mental model: AI decides. Your code does the engineering.

4. What will AI change in design engineering?

Copy this prompt

List 10 tasks in a design engineering team that AI will change in the next 3 years, and 5 it won't. Be specific to drawings, BOMs, standards, and design reviews. Say how confident you are in each.

Then ask

Which of these tasks need clean, structured CAD data before AI can help?
Which skills make a design engineer more valuable as AI spreads?

A good answer mentions

Specific tasks: drawing checks, property and BOM cleanup, standards questions, finding similar past parts, documentation.
What stays human: engineering judgement, design intent, sign-off and responsibility.
A point about data: AI is only as useful as the CAD data it can reach.
Honest uncertainty. Treat bold predictions with a pinch of salt and ask for sources.

Mental model: AI multiplies tool builders. Judgement stays human.

Sunday morning · 45 minutes: AI in CAD

AI in CAD: what is happening now

Every major CAD vendor shipped or announced an AI assistant in 2025 and 2026. They fall into three groups.

Type	Examples	What it does
Q&A assistants	Onshape AI Advisor (PTC), Design Copilot NX (Siemens)	Answer how-to questions from documentation and best practices
In-app copilots	SOLIDWORKS companions Aura, Leo, Marie (Dassault, announced Feb 2026). Autodesk Assistant for Fusion, Inventor, Moldflow, Vault (tech preview, June 2026)	Turn natural language into modeling steps and API calls inside the CAD tool
Agents through MCP	Autodesk Fusion MCP and Fusion Data MCP servers. Community MCP servers for SolidWorks, FreeCAD, CadQuery	Let an outside AI model call CAD functions and read design data
Text-to-CAD	Zoo Text-to-CAD, CadQuery and build123d code generation, research such as Text2CAD	Generate geometry by writing CAD code from a prompt

Look at the in-app copilots and MCP servers closely. Autodesk calls one feature prompt-to-API. Every one of these ends in an API call. The people building them are CAD automation engineers who added AI.

Mental model: AI decides. Your code does the engineering.

Vendor features change fast. Check each vendor's own pages for what is released and what is still a preview.

CAD copilot projects you can build

Project	What it teaches
Standards Q&A bot: ask your drawing standards questions, get answers with the clause cited	Embeddings, vector search, RAG
Property normalizer: clean messy material and description fields into structured JSON	LLM APIs, structured output, validation
Natural-language part search: "find brackets in S355, 3 mm thick"	CAD data extraction, metadata search
Drawing checker agent: AI calls your C# checker and explains failures	Tool calling, MCP servers, approvals
API code helper: prompt to SolidWorks macro, tested on a sample file	AI at dev time, code review
Text-to-bracket: AI writes CadQuery code for a simple part, you validate it	Code-generated CAD, geometry checks

Practical topics to learn for AI in CAD

Using AI to write and explain CAD API code, and verifying every call against the docs.
LLM APIs: messages, tokens, cost, structured output with JSON schema.
Extracting CAD data (properties, features, mass, BOM) to JSON so AI has something to read.
Embeddings, vector databases, and RAG over standards and manuals.
Tool calling and MCP: exposing your own CAD functions to an AI model.
Guardrails: validation, human approval before writes, logs, test sets.
Data privacy: what may leave the company, and local models such as Ollama.
Geometry basics: B-Rep vs mesh, STEP files, what AI can and cannot reason about.

Sunday afternoon · 30 minutes: prepare and learn

How to prepare

Pick one CAD platform: the one you use every day. Go deep before going wide.
Log your week: for five days, note every task you repeat. That list is your project backlog.
Write your team's rules down: title block fields, revision format, material names. Code needs explicit rules.
Learn the vocabulary: API, object model, macro, add-in, COM, .NET, custom properties, PDM.
Set up the tools: Visual Studio Community, your CAD's API help file, and Git for version control.
Keep a portfolio: small tools on GitHub, built on your own sample files. Never upload company files or code.
Search job posts for: CAD automation engineer, design automation engineer, SolidWorks API developer, KBE engineer, Revit API developer. Read the skills they list.

How to learn it

Step	What to learn	First project
1	C# basics: types, classes, lists, loops, exceptions, debugging	Console app that validates a BOM CSV
2	Your CAD API object model, using the macro recorder as a map	Read and write custom properties of the open part
3	Batch processing and error handling	Export every drawing in a folder to PDF
4	Add-ins: ribbon button, task pane, logging	One-click drawing checker for your team
5	CAD data: JSON, SQL, REST APIs	Extract every part to JSON and report mismatches
6	AI layer: LLM APIs, RAG, tool calling	An assistant that calls your own checker

Search for learning resources for your platform and judge what you find:

Does it start from where a design engineer is, or assume you are already a programmer?
Is it one structured path, or scattered topics you have to stitch together?
Do you build real tools on your own CAD platform?
Is it current, and is the cost reasonable for what you get?

What you will probably notice: free material exists (official API help, blogs such as CADSharp and CodeStack, forums, YouTube) but it is scattered. Structured courses often cost a lot or come bundled. Judge for yourself.

Monday to Wednesday · 5 minutes a day: let it sink in

Don't study more. Write one sentence a day. Your brain keeps connecting the pieces in the background.

Day	Write one sentence
Monday	Write what a CAD API is, in one sentence, in your own words.
Tuesday	Name one task in your team that is repeated every week. Could code do it?
Wednesday	Where could AI fit into that task, and what would your code need to check?

Thursday · 10 minutes: are you ready to start?

If this guide made sense to you, you have the foundation. Tick what is true:

You can explain what a CAD API is in one sentence.
You know why C# is used for CAD and Python for AI.
You can name two industries and two projects that match your own work.
You can explain why every AI copilot in CAD still ends in an API call.
You have one task from your own week that could be automated.

If you ticked these, you are ready to start learning CAD automation. That is exactly where ScriptedCAD Workbooks begin: from your first line of C# to a working SolidWorks add-in, step by step.

Free community: join the ScriptedCAD WhatsApp group to discuss this guide. We share tips, roadmaps, and guidance every week.

Want the full path? Get the free roadmap: From Design Engineer to AI Engineer in CAD.

Sources for the AI in CAD section

Digital Engineering 24/7, 3DEXPERIENCE 2026 AI companions (Feb 2026).
Digital Engineering 24/7, Siemens AI copilot for NX (Jul 2025).
MONOist, Autodesk Assistant and Fusion MCP (Jun 2026).
All3DP, Onshape AI Advisor (Oct 2025).