"Handle Layers" links to original Rhino layer and objects end up in multiple Collections

[joel-putnam]

When re importing a Rhino file that was previously imported but a user "rearranged" the Blender Collections the "handle layers" functions links the original object to two Collections.

Steps to reproduce the behavior:

1. Create a cube in rhino on the default layer and save file
2. Import the Rhino file into Blender
3. Create a new Collection
4. Move the imported cube to the new Collection
5. Re-import the Rhino file

The cube should not be linked into two Collections. Or maybe this should be an option? Personal I would not like this behavior as default

[jesterKing]

I see here several strategies necessary that can be controlled via an option:

• allow multiple layers: current behavior
• link to imported layer: clear existing link to layers and link to layer as designated by the imported file
• keep current layer(s): skip linking to layers

[joel-putnam]

Yeah these seem great.

[lfertig]

i think this issue is not exclusive to layers, the same thing is going to happen with groups and eventually also with blocks. just to keep in mind to also look at these data handlers..