VBA vs C# for SolidWorks Automation: Which Should You Learn?

Both talk to the same SolidWorks API. The object model — SldWorks, ModelDoc2, FeatureManager, Dimension — is identical, the method names are identical, and the metres-not-millimetres rule is identical. What differs is where your code lives, who can run it, and how far it can grow. That is the whole decision.

What a VBA macro is good at

• It is already there. The VBA editor ships inside SolidWorks; Tools → Macro → New and you are writing code. No install, no IT ticket.
• Record first, edit second. The macro recorder writes the first draft; you learn the API by reading what it recorded.
• Instant feedback. F5 runs it against the open document. For a one-off job — rename 40 features, export this drawing to PDF, set every hole to 6.5 mm — nothing is faster.
• Easy to share with one colleague. A .swp file on the Macro toolbar.

Where it stops: a macro runs inside SolidWorks' process, so it cannot run on a schedule without SolidWorks on screen; user interfaces are VBA forms (fine for a few inputs, painful beyond); there is no real version control, unit testing or packaging; and a macro cannot be installed as a tool that appears in the SolidWorks menu for a whole team.

What C# is good at

• Standalone programs. A console app or Windows app that connects to SolidWorks (Marshal.GetActiveObject("SldWorks.Application")) or starts it. Batch jobs over a folder of parts, overnight exports, configurators that read a table.
• Add-ins. A C# class library registered with SolidWorks becomes a toolbar, a task pane or a property manager page — a real product your team installs once.
• Proper engineering. Visual Studio, IntelliSense from the interop assemblies, git, tests, NuGet, installers.
• Everything else .NET can do: databases, Excel, PLM/ERP APIs, web services — the automation stops being "inside CAD" and becomes part of the company's systems.

Where it costs more: Visual Studio and the COM interop references to set up; a compile step between change and run; and for a one-line fix on one part, it is slower than a macro.

The honest comparison

	VBA macro	C# program / add-in
Setup	none, built into SolidWorks	Visual Studio + interop references
Best for	one-off fixes, personal helpers, learning the API	tools for a team, batch jobs, add-ins, integrations
Runs	inside SolidWorks, with it open	outside it (standalone) or inside it (add-in)
User interface	VBA forms	WinForms/WPF, task panes, property pages
Sharing	copy the .swp	installer, add-in registration
Growth	gets unwieldy past a few hundred lines	scales with normal software practice
API knowledge needed	the same	the same

So which first?

VBA first, then C# — and do not stop at VBA. The macro recorder is the fastest way to learn what the API calls are, and every hour you spend on the object model in VBA transfers to C# unchanged. Once you have written three or four macros you will hit the ceiling (a form that needs a grid, a job that should run on a server, a tool a colleague wants on their toolbar), and that is the moment to move to C#.

That is also the order the SolidWorks API & Automation Course teaches: the full API course opens with VBA macros and moves to C#, and the API + C# course adds the C# foundations for engineers starting from zero. The hub page lists every SolidWorks course, with the trial lesson first.

Three quick decision rules

1. Will anyone but you run it? C#.
2. Will it run on more than one file at a time, or without a person watching? C#.
3. Is it a one-off on the part in front of you? VBA — and record it rather than typing it.