Shading Groups Missing?

[user_deleted]

I have some objects, with shaders assigned to them.
Everything was fine, but now they're appearing grey...
Attribute editor does show the tab of the proper material...
If I reassign the material, it works, but I'm wondering if I can automate fixing this?
I suspect it's a broken / missing shading group issue maybe?

[longrayjohnson]

do you use renderlayers ? if so this might be caused by deleting shaders, or material overrides on renderlayers. if this is the case, you have my sympathy. i had to redo scenes a thousand times after using those shitty renderlayers without proper caution. have not found a cure yet.

[user_deleted]

thanks. Yeeea, I'm using render layers, and I have to. And yeeaaaa, I'm pretty sure that's the problem.

Can you define

QUOTE
proper caution

?

Because I'm happy to be thorough and careful, even if it's limiting. Right now though, I just don't get the logic. Shaders get blown away all the time and I can't figure out what the "things not to do" are.

Don't say "don't use render layers". I won't, on the next production.

[longrayjohnson]

hy,

we have to use renderlayers too on heavy scenes and it works if you don't do certain things. i am not entirely sure, but i found that i am not having those problems you mention, when i do not delete any shaders once i have created the first renderlayer. that seems to be logic, as renderlayers organise the connections between shading groups, renderlayers and objects. so as those connections are quite complicated it is understandable that deletion of one of those connections seems to cause trouble.also what i never do is use material override on a renderlayer, as this seems to fuck up the scene. once you done that you get those silly errors that you can't assign a shader on another renderlayer and if you can they loose connection when you change on renderlayers. i think it has got to do with the fact, that this override locks the object so you can't assign another shader, what is logic, but i doesn't seem to work properly and even if you removed the override some sort of information seems to stay in the scene.
the only cure once you have that problem seems to be to delete all renderlayers and rebuild them from scratch. that really sucks, doesn't it. i lost a looot of time doing this, what is really annoying especially the night before deadline.

[user_deleted]

Ok - thanks for the list of tips. I will try to stick to them.
What an absurd mess!