Linking Node values

Lets say I have 2 different materials with a glossy shader. I want to link the Roughness of both shaders so that they will always be the same, just by changing one.
Is this possible?

just use the ‘value’ node from the input group, and connect the value to both shaders.

The shaders are on different objects. They are not the same material either.

maybe using a node group, with the value node inside… this way you can share outputs with different objects.
it’s not very pratical, in the sense that you need to go inside the group to change the value. But all the materials will reflect the changes automatically.

Custom Property set on one object can drive parameters of all Scene materials.

http://www.pasteall.org/blend/30260

Select Cube and slide Custom Property value for it.

Thanks Eppo,
Is there any way you can give me a quick rundown? This is new territory for me.

I got the know-how here http://vimeo.com/40389198. But that’s a lot more than is needed this time.
Add one property to Cube and open Graph editor, set it to show Drivers. Add driver to node in node editor by rightclicking on node slider.
In graph editor (you’ll see the right line there, click on it) delete values, add new, set it to be from Objects, Cube, and copy in data path from created Custom Property (rightclick, Copy Data Path).

Or if it’s only used in materials and you want to avoid drivers, just put the value in a node group.

I think I lost you…, but Ill experiment when I get home.

Yeah, i know this was too condensed… If seeing interface does not make sense just pm. I’ll try to go detailed then.
Check example in previous post.

Thanks guy, I got it working.