Getting Started with SolidWorks PDM API

PDM API vs SolidWorks API

The SolidWorks PDM API is a completely separate COM library from the SolidWorks API. They share no interfaces. The key differences:

• SolidWorks API: Controls the CAD application — models, features, drawings, geometry
• PDM API: Controls the vault — files, folders, workflows, variables, users, revisions
• Different DLLs: PDM uses EPDM.Interop.epdm, not SolidWorks.Interop.sldworks
• Different threading: PDM API can run in background services; SolidWorks API requires STA

Setting Up Your Project

1. Create a .NET Framework class library project (PDM add-ins must target .NET Framework, not .NET 5+)
2. Add a reference to EPDM.Interop.epdm from the PDM installation folder
3. Add a reference to EPDM.Interop.EPDMResultCode for error handling

The Primary Interop Assemblies (PIAs) are typically found in:

C:\Program Files\SOLIDWORKS PDM\EPDM.Interop.epdm.dll

Connecting to a Vault

var vault = new EdmVault5();
vault.LoginAuto("MyVaultName", 0);  // Uses Windows auth

LoginAuto uses the currently logged-in Windows user's credentials. For explicit login:

vault.Login("username", "password", "MyVaultName");

Reading File Information

IEdmFile5 file;
IEdmFolder5 folder;
vault.GetFileFromPath("C:\\Vault\\Parts\\Bracket.sldprt", out file, out folder);

// Read file variables (custom properties in PDM)
var varMgr = file.GetEnumeratorVariable("");
string partNumber = "";
varMgr.GetVar("PartNumber", "@", out partNumber);

// Get current workflow state
var state = file.CurrentState;
Console.WriteLine($"State: {state.Name}");

Types of PDM Development

Standalone Applications

Regular .exe programs that connect to the vault externally. Good for batch tools, reports, and integrations. Can run without PDM client UI.

PDM Add-ins

DLLs that load inside the PDM client. Respond to vault events (file check-in, state change, etc.) and add custom menu items. Must implement IEdmAddIn5.

Task Add-ins

Special add-ins that run as scheduled or triggered tasks on the PDM task host. Used for conversion (PDF generation), data synchronization, and automated workflows.

Dispatch Scripts

No-code automation built into PDM. Can execute programs, send emails, and manipulate files based on workflow transitions. Good for simple automation without writing code.

Common Pitfalls

• Vault login scope: Each process needs its own vault connection. Don't share EdmVault5 across threads
• File locking: Always check a file out before modifying it, and check it back in when done
• Variable scoping: Variables can be file-level or configuration-level, similar to SolidWorks custom properties
• Testing: You can't easily unit test PDM code — use a test vault and integration tests
• Deployment: PDM add-ins must be installed on every client machine via the PDM admin tool