2011 mia/misss bump bug

[Sagroth]

When you connect and then disconnect bump node from standard_bump (or
overall_bump) of mia shader (or bump of misss), it's value remains 0 0
1 and in 2011 this shader gets screwed up. In 2009 it remains 0 0 1
also, but renders without any problems and that was never an issue.

So, when I open one of my 2009 scenes in 2011 - some swatches get
black and materials render flat, because at some point I'd
disconnected bump from them. I have to type something like this for
each shader:

setAttr .standard_bump -type "double3" 0 0 0;

and it gets corrected.

Noticed this in the very first 2011 release, but figured out the
problem and solution just today ('cause it's still present in SP1).

[David Lawson]

after you unplug the bump you need to turn the mode to 0 from 5.

[Sagroth]

In mode 0 it will use mental ray bump slot instead of overall_bump/
standard_bump, which will still remain broken, so that's definitely
not a solution.

In my particular case I've disconnected bump from standard_bump and
connected it to overall_bump :)

[David Johnson]

I have not had time to look at the problem in 2011, but sounds like
the same as in 2010.
I fixed it then, with some mods to a couple of mels.

http://www.djx.com.au/blog/2009/10/15/maya-2010-mia_material_x-bump-bug-fix/

Maybe these mods can also be applied to 2011.

[Sagroth]

Wow, this bug is older than I thought. Thanks for the tip - I'll try
it.