SSM Event Regression - AutoCAD 2026.1.1 (Connected Sheet Set Manager)

Summary

The Sheet Set Manager COM event API (IAcSmEvents) is broken in AutoCAD 2026.1.1 (Connected Sheet Set Manager update). The documented ACSM_DATABASE_OPENED event no longer fires when opening a .dst file. Instead, an undocumented event code 30 is dispatched, and IAcSmPersist.GetDatabase() returns NULL.

This is a regression from AutoCAD 2026.0, where the API works correctly.

Environment

Component	Working	Broken
AutoCAD version	2026.0	2026.1.1
SSM implementation	Traditional (file-based)	Connected Sheet Set Manager (cloud)
.NET	8.0	8.0
Platform	x64	x64

Expected Behavior (AutoCAD 2026.0)

When a user opens a .dst sheet set file:

1. IAcSmEvents.OnChanged fires with AcSmEvent.ACSM_DATABASE_OPENED (code 16)
2. The comp parameter is a valid IAcSmPersist object
3. comp.GetDatabase() returns a valid IAcSmDatabase reference

Actual Behavior (AutoCAD 2026.1.1)

When a user opens a .dst sheet set file:

1. IAcSmEvents.OnChanged fires with undocumented event code 30 (not in AcSmEvent enum)
2. comp.GetDatabase() throws NullReferenceException
3. ACSM_DATABASE_OPENED (16) never fires
4. ACSM_DATABASE_LOAD_COMPLETE never fires

Impact

Any third-party plugin that relies on IAcSmEvents to detect sheet set open/close operations is broken in 2026.1.1.

Reproduction

Prerequisites

• AutoCAD 2026.1.1 with Connected Sheet Set Manager
• ObjectARX SDK (2026)
• Visual Studio 2022 (Developer Command Prompt)
• Any valid .dst file

Build

From Developer Command Prompt for VS:

build.bat "C:\path\to\ObjectARX_SDK"

The build generates the COM interop assembly from the SDK's acsmcomponents25.tlb via tlbimp - no additional binaries required.

Output: bin\x64\Debug\net8.0-windows\EventTest.dll

Run

1. Start AutoCAD 2026.1.1
2. NETLOAD -> select EventTest.dll
3. OPENSHEETSET -> open any .dst file
4. Check %USERPROFILE%\Desktop\SSM_EventLog.txt

Sample Log

AutoCAD 2026.0 (correct):

[...] [ExtApp] Registered IAcSmEvents handler, cookie=1
[...] Event: ACSM_DATABASE_OPENED (code=16), db OK, class=...

AutoCAD 2026.1.1 (broken):

[...] [ExtApp] Registered IAcSmEvents handler, cookie=1
[...] Event: UNKNOWN(30) (code=30), db threw: NullReferenceException: Object reference not set to an instance of an object.

Files

File	Description
EventTest.csproj	SDK-style project (.NET 8); generates interop from TLB
arxmain.cs	Extension entry point; registers IAcSmEvents handler
SSMEventHandler.cs	Event handler; logs all events to Desktop
build.bat	Build script; accepts SDK root path as argument

Evidence

See evidence/ folder for log files and screenshots from testing on both versions.

Questions for Autodesk

1. Is event code 30 intentional for the Connected Sheet Set Manager? If so, what is its meaning and when will it be documented?
2. Why does IAcSmPersist.GetDatabase() return NULL for event 30?
3. Is ACSM_DATABASE_OPENED (16) intentionally removed, or is this a regression?
4. What is the recommended migration path for existing IAcSmEvents consumers?