It seems very unnessesary to export materials with images when all I export are curves.
Do you know what the logic is?
I can understand the logic regarding the HDRI as an environment, but ExportSelected indicates that ONLY the selected objects will be exported and not the scene data.
And on opening the file I ran Purge and it had 20 unused materials…
Those should not have been included in the export IMO.
Of course it IS possible to assign materials to curves (curve thickening,) so it’s not really up to “Rhino” to say this makes no sense arbitrarily.
I tried a test and if I turn off “export plug-in data” then on a model with Rhino materials it only exports the RDK materials assigned to layers or curves. With “export plug-in data” on I get all (maybe all?) the materials…which makes a certain amount of sense as “plug-in data” could be anything and how does it know what you don’t want? (Non-RDK iRay only exports used materials, so it’s apparently up to the plug-ins to determine what should be exported.) But that doesn’t quite align with turning that off still exporting some materials, there’s some ambuguity over whether RDK materials are “plugin data” or not.
I think the issue is that with copy/paste any rhino object you get all materials that are in your document too.
Which is really not a great thing if you copy a simple curve out of a huge file with tons of materials into a new clean file and end up with a file that has one curve but a file size of half a gig that takes 30 seconds to open…
Yeah, this has always seemed a little, well, wrong, 90 % of the time, to me.
-Pascal
I thought there was a YT item for it, but my search skills leave me empty-handed.
Somehow related to this - not sure if this is by design and what logic behind it is: I have a file with 300 meshes, each has an individual material assigned. I Export Selected each of them into a separate Rhino file. Now each of the files contains all 300 materials, not just one from the exported object. So the exported file size is big, until I open and purge each. Why do we need all materials in the destination file? Seems like an unnecessary overhead…
I wish my feelings were as polite regarding this topic as your expression of the topic 
This really needs to be fixed. Exporiting anything not related to the selected objects in a “export selected” process is a bug. (not technically from a nerdy programmers point of view, since the code obviously does what it should, but user related, from a customer point of view it is malfunctioning software IMO)
It’s not easy, and my feelings are less polite than what I wrote Unless explicitly specified by the user as an non-default option, when Exporting Selected to Rhino file, only the information pertaining to the selection should be left in the file.
With what we are working right now the current bug creates a lot of mess and time loss to batch process 1000s of files to purge them from the info we didn’t ask for to be included. Yes, can we please have it fixed?
(It’s one of rare cases when we, users, actually want Rhino to do less, not more!)
All the more surprising that this bug has been reported two years and 15 service releases ago (it’s in youtrack) and re-reported many times since - and nothing has been done…
Surprising not giving this higher priority if it’s been known for a while - most users would not even be aware of what’s going on, just see “slowness” or system resources being eaten up by Rhino with all the extra junk nobody expects when copying or exporting. YT shows slated for 7.x. IMHO it should be V6 SR fix : /