how do you add multiple materials to an object, not for seperate parts of it, but layered on top of each other?
you can’t [unless you start duplicating your mesh…]
only textures
which you can have up to 8 per material
http://www.blender.org/modules/documentation/htmlI/c4431.html
awww
that’s no fun 
oh well, guess that just forces me to be more creative 
what are you trying to do?
You can have up to 16 materials per mesh also. In the editing panel (F9) there is a box to make multiple materials. You then make the materials single user and assign materials to groups of vertices. You can’t layer these materials like the layered shaders in Maya but I think it’s probably what you’re looking for. Check to see if this is what you want:
http://www.blender.org/modules/documentation/htmlI/x4272.html
z3r0 d: i am trying to make worn polished wood, like the actualy bar in a bar,
and an ivory or bone type material
i was hoping to have a layer with a low hardness value for a kind of dull sheen with a higher hardness over it
osxrules: actualy i was trying to layer them
thx for the help anyway
Greybeard has the answer for you:
https://blenderartists.org/forum/viewtopic.php?t=27741&highlight=material
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Ah, I see. I’m not sure if Fligh’s link will help either. It sounds like you want a subsurface scattering effect, which I don’t think you can do in Blender without adding extra geometry. Someone did something like that with an embryo but had to duplicate the geometry, scale down and tweak the alpha values of each layer.
In real life, a bar top has a physically thick layer of polyurethane varnish. It’s easier to simulate with subsurface stuff but you could just duplicate the table top and move it up a fraction in the z-axis. Then make this layer have different values but make it transparent with some refraction index>1.
I’m not entirely sure I follow your description though, so I could be totally wrong. Do you have an image/photo of what you want to recreate?