"What" command and "UserData ID"

Hello everyone,

Today I realized that on top of the classic ID assigned to a geometry, there is also something called “UserData ID”. However I fail to understand its implications.

I found curious that in some files/geometries, there is no UserData ID, while others can have even more than one. Again, I tried to make some test and replicate it but it wasn’t possible.

I wonder if this can be related somehow to the computer of the person that created the file… And thus, I reopen the old-eternal-never-to-be-solved problem of the plagirism.

Thanks in advance for any hints or help.

Hello- presumably various plug-ins or other processes have ways of adding their own user data to objects and that use the ID to manage that - I am making this up, but that would be my guess. I’ll see if a bigger brain has a better answer.


Both plug-ins and Rhino itself can add user data to objects. And although this information might give some clue how the object is constructed, it’s not conclusive. In many cases, the user data has nothing to do with how the object was created, custom rendering information for example.

Can you share a screen capture of Rhino’s What window?

– Dale

Thanks @pascal and @dale for your response.

It turns out that the same files, now opened from a different computer don’t show any “userdata ID” information. Therefore I conclude that my own laptop (I can’t check it rightnow) was producing that data… it does not seem to be a very reliable behaviour for detecting plagiarism.

Maybe this helps?

– Dale

It does help. Very interesting tool…! Maybe for next year.
I feel someone should do a PhD based on how to avoid the students from copying hehehhe.