Why do nested Block Instance GUIDs change when the parent Block is edited?

Steps to reproduce:

  1. Create a Block with a nested Block
  2. Edit parent Block
  3. Select and look at Instance ID of nested Block
  4. Exit Block Edit
  5. Edit parent Block again
  6. Select and look at Instance ID of nested Block, it has changed.

I was hoping that the IDs were persistent for tracking purposes.

Hello - I see that, I don’t know what the process is but presumably on editing a block a new block is created, under the hood, with new instances internally. You can try adding UserText to the instances as a marker - that persists.


I believe it is this bug:


It exists in Rhino 5 also.

No doubt, but there is no longer development in v5 going on.

understood. I’m perfectly fine with that.