Hello! When working in Blender I often have objects with different autosmooth settings and in the end I save the object normals with Geaometry Data >>> Add Custom Split Normals Data.
Then I combine these objects. This is very easy to do if you have no more than ten objects, but when there is a need to apply this tool to a larger number, then I tried to do it by selecting all objects and holding Alt before clicking on Add Custom Split Normals Data. I expected this function to be applied to all objects, but only got the effect on the selected one. And so in many tools (for example, when adding a UV Map, a new material or a modifier).
(In simulation systems, I was sometimes able to apply changes to all selected objects)
I would like to know if this is a conscious decision of the UI / UX team not to allow such interaction with many objects, or is it just the lack of such functionality? (I suspect not to crash Blender with a huge amount of data)
And the last question, how can the user find out which tool supports the ability to be applied to all selected objects and which does not? (Maybe it can be done in the tips)
If this is important, then I used versions 2.83.5 and 2.9 for testing. thanks
Hi, afaik multi-object property editing is incomplete, but this in particular is not a property anyway, but an operator. To work around it you can simply loop over the relevant objects and call the operator. Usually that’s the way to go when batch-doing-things.
Hello! Thank you for responding! I have scripts (bike :)) in Python to solve some of these problems (for example, with UV Map and adding a normal layer), I just wanted to know if this is a conscious limitation for users, or the functionality is just in development. From your answer, I understood that we just need to wait for the built-in solution in Blender.
Forgive me if I make the wrong sentences, English is not my native language.
I can’t say for sure whether multi-property editing, even once polished, would even apply to this specifically since it is not actually a property. I think @mont29 would be the one to ask. (I hope it’s ok to ping you Bastien)
No worries -mine is french, and a fair number of people here are not native speakers either.
Nothing to add to your answer @Hadriscus, indeed operators are not concerned by multi-properties editing.
Thank you guys for the answers.
Wouldn’t it be convenient if holding Alt could trigger all possibles functions to all selected objects, wherever it makes sense?
It should be possible to simply select multiple objects and edit all their proterties or shared operators everywhere, program wide by default with only very few exceptions where logically absolutely necessary. Just like in nearly every other software (though Maya for example is also super inconsistend and weird with this). And you should not have to hold any option key for it or even have to know about it in the first place (still one of the top non discoverable features in Blender). Though I’d be totally fine with holding [Alt] as an option key for any property if it worked and was documented more frequently in tooltips. Or maybe the inverse - if there are multiple things selected then operate on all of them and use alt to single out only the active one.
Either way - doesn’t matter as the usual problem applies: There is nobody to pick it up, currently and it’s a very complex topic if done right. Because as usual it sounds like a simple thing in theory until you realize that there is more to it in terms of predictability and consistency of usage and performance (multi properties need to iterate over everything to check which things are shared).
Devtask exists for five years now:
know someone who is capable and willing to tackle it? By all means - go for it. I’d be one of their biggest fans from this day on. I keep mentioning this like … all the time. 
As mentioned in the blue bar on top of every page
For feature requests, please use rightclickselect.com. For questions about how to use Blender, ask on one of the community forums.
necromancing a 2 year old thread hoping to sidestep these rules sadly isn’t gonna work.