Change to the Material SubObject Assignment is not Wanted

[ed.p.may]

Hello,

I just wanted to voice an objection to the change in the way Materials are handled when assigning sub-objects. As a result of the latest update (Version 7 (7.21.22208.13002, 2022-07-27)), now when I apply a Material to Sub-Object, my materials palette gets cluttered up by the automatically added ‘Custom’ materials. This is not desirable and I would like it to behave how it did before the recent update (ie: it did not fill up the Marerials with ‘Custom’ materials every time I make an assignment.)

Scenario:
Multiple closed polysurfaces, with sub-faces. Assign materials to certain faces:

create a single Material and assign it:

a new ‘Custom’ Material is created for each Brep:

This happens every time an assignment is made, adding a huge number of ‘Custom’ materials to the set. Add new brep, assign material, get a new ‘Custom’ material:

This is not a good change and needlessly adds duplicate materials to the file, making material management hard (and confusing). I would prefer if it did not do this, and instead operated like it did before this recent update (where it did not add these extra materials all the time). I use this technique quite often, so I know it worked fine a week or two ago.

---

Environment:

• Macbook 2021, Apple M1 Max
• OS 12.5.1 (Monterey)
• Rhino Version 7 (7.21.22208.13002, 2022-07-27)))

Thank you very much,
-Ed
@ed.p.may

[jeremy5 (Jeremy)]

Hi Ed,

Pending a fix for this problem, you may be able to tidy up the mess with the RenderMergeIdenticalMaterials command. No promises - I haven’t used it myself, just noted it in passing.

HTH
Jeremy

[milezee]

yeh I’ve noticed this, so messy, not helpful when you make efforts to be organised in general

[ed.p.may]

@jeremy5

RenderMergeIdenticalMaterials

Thanks @jeremy5

That is a good idea, unfortunately when using the RenderMergeIdenticalMaterials command, it seems that only one of the sub-object assignments survive the merge (though it does remove the extra ‘Custom’ materials)

1. Two Breps, each with the same Material applied to a Face:
   

   

2. Run RenderMergeIdenticalMaterials command

3. Custom (1) is removed, but then the ‘second’ Brep losses its subface material assignment:
   

   

it was worth a try though! Thanks,
@ed.p.may

[jeremy5 (Jeremy)]

Sorry it didn’t help Ed. I think it ought to but the failure you note is either an unconsidered use case or a bug: maybe @pascal could see if it’s something that could go back to the devs.

Regards
Jeremy