Deselecting object with multi-edit poly modifier breaks one of the objects within the selection of the Edit Poly

[jesseKULF6]

In the attached file, I have 109 cabinet doors. Each object is made of 1-3 separate meshes. For each cabinet there is supporting reference and tool objects for measurement. 

Twice now, in the file, after editing 2 objects with 1 edit poly modifier, the cabinet frame object has become corrupted. Something is happening in the objects modifier stack that destroys only 1 of the 2 objects in the multi-edit poly. 

One of my coworkers mentioned that she had talked to an Autodesk rep at a convention - they had mentioned that this sort of thing should no longer be happening. She advised me to send it in.

The error ultimately happens when I am finished editing the objects and I deselect them.

Edit: 3DS Max 2025.2 | 27.0 - 27.2.0.20885

[MartinBeh]

Which version of 3ds Max are you using?

[jesseKULF6]

[MartinBeh]

Thanks for the version info and the .max file - could you maybe also provide some 1,2,3 steps to follow with the .max to reproduce your issue?

[jesseKULF6]

Difficult to describe where things are going wrong through text but the attached video describes where I think I am messing it up. I may have solved my own problem. 

[MartinBeh · Accepted solution]

Thanks for the video!

It looks like you need to keep the Edge sub-object mode active in the top-most Edit Poly modifier of Rectangle017, which is instanced to Rectangle016 where the sub-object mode seems to affect the first Chamfer modifier in Rectangle016 (which is set to Selection = From Stack).

So I suggest the following fix:

Select Rectangle016 and in the modifier stack, activate the second "Edit Poly" modifier from the bottom and switch it to Edge sub-object mode.

There seems to be some sort of bug which causes the sub-object to be turned off if you directly switch to another object, so you need to first select a modifier higher up in the stack before selecting another object. With that the sub-object mode is retained and the Chamfer modfier gets the needed input.

Unfortunately, this very same thing will happen again! as soon as you select Rectangle017 in Modify mode and then select something else.

--> Now we know about this bug in Edit Poly, the best fix to this is to add another "Poly Select" modifier on top of Rectangle017 and switch that one into Edge sub-object mode; this will stick.

(I will try to report this Edit Poly bug to the developers)

BTW: Your stack is quite complex, and all modifiers of same type have the same names - this makes it rather hard to understand what is going on, so I would suggest to rename the individual modifiers, e.g. by appending a unique number.

[jesseKULF6]

Excellent! Thank you for your help and for a good solution.