Get Plug-in Data

I am looking to try to write a python script that will retrieve some of the user data that was placed on a object by a plug-in. According to the Rhino details some of the geometry has been placed as Attribute User Data and some has been placed as Geometry User Data. I was wondering if someone could give me an example of how to do that. The example below shows how to place geometry but not retrieve it.

In general, it is not possible to read the user data added by a plug-in that you did not write. To read user data, you will need the user data class (definition), which is something you may not have if you didn’t write the user data.

More information on what you are trying to read or do might be helpful here…

Humm seem counter intuitive to me, but I am not a programmer. So I can’t access data stored in a Rhino document unless I have the specific class that created it?? Isn’t the data written into the document and shouldn’t there be a way to retrieve from the document after it’s written into it?

I am using the plug-in RhinoBIM to model some structural elements, what i would like to do is move each member from it’s existing layer to layer that matches the size of the member. For instance I want to move all HSS3x3x1/4’s to a layer called HSS3x3x1/4.

Keep in mind that Rhino has no idea what the plug-in has written to the document as user data. Only the plug-in know the structure of what it’s written. To Rhino, user data is just an anonymous block of binary “goo” that can only be read by the owning plug-in.

Sure there is. The plug-in that wrote the user data knows how to read the data.