the material browser have changed the last revit versions, but I think the tutorial is still useful: Watch the Online Video Course Revit Architecture: Rendering

I've gone through the entire video previously (2-3 times)...problem is that he talks about material property sets (RVT 2012) and I am using 2014 which references material assets...and they do not operate the same way as in his video...driving me nuts!
I try to create my own custom texture library by using an existing material asset from the Autodesk library and modifying it inside my own library. When I save it, the material reverts back to the original state without my edits...not sure why. Really could use some assistance with creating a material, adding a new texture to it from an image I created, then applying it to a wall.

Why does a "duplicated" material, when edited, change the original material?

This goes out to the render "whiz" amongst us...
I am trying to use a material, white stucco, to create a new material. I then change the image file to one I created, change the bump map to one I created, and then save the new edited material. It then changes both the material I created and the original one it was copied from. This is driving me CRAZY!:crazy:
I would really appreciate a step-by-step on this one. I already viewed the Lynda.com video on this but they reference RVT2012, I am using 2014 and the material editor and terminology is different (properties versus assets, etc.)

Be sure that your duplicating the appearance asset...if you try modifying the original it will stick with the original as its locked.

I think it helps to understand what Material Assets (MA) are doing (this might be just my interpretation).

Imagine you've got multiple Revit Materials (5/8" GWB, 5/8" Type X GWB, 1/2" GWB, etc. as one example) and you want them all to be painted the same color... and that color might change during the project. Without MA you'd have to hunt down all the Materials that needed changing and update them one-by-one. With MA you only need to change it once and it updates all Materials using the Asset.

So, if you need a new Material with different rendering appearances you'll need to duplicate, as others have said, the Asset as well.

Be aware that if you duplicate a material, the duplicate still refers to the same assets as the original did. Changing those asset's properties will cascade to both the old material and the new copy. Because Revit uses materials in many ways, a simple appearance based model is insufficient. To make things more difficult yet, different disciplines look at materials in different ways, thus to an architect there may be four different concrete types based on appearance, to an engineer there may be three types based on strength, and to an energy analyst, there are two types, standard and lightweight. The asset based model attempts to organize this condition by providing buckets of properties that can be combined to define a specific material that will be used. Assets as independent data elements allow each discipline to control the material properties they care about without too much interference. They also allow you to manage a set of related materials that to you are essentially the same even though in reality they are different in ways you don't care about. As Greg says, this means you can define a specific paint color or concrete finish and use it as the appearance for many materials. An engineer can use a consistent set of strength properties across all instances of A36 steel without managing multiple parallel elements.

How do I duplicate an "asset"? When I go to the asset browser, there are is an "appearance library" in one folder and "Autodesk physical assets" in another folder. There is no choice to "duplicate" or copy an asset...so how do I "duplicate...the Asset as well"?

It's the little icon with 2 sheets of paper to the right of the Asset type...(Next to the Replace this Asset icon for where you create a new material and want to apply a specific material asset to it)

To the left of the Asset Type is a hand with a number above it....it shows how many materials are sharing that Asset Type...

I'm pretty sure you could say that if you duplicate a material then the only area you can change without graphically affecting another material via the asset is the graphics (in program)tab. Soon as you go into the appearance (rendering) tab you are affecting the asset, and by looking at the small icon you can see how many other materials are using that asset, and therefore being affected immediately. I am trying to think of a good analogy but can't just yet.
Now I understand how it works I see the sense especially after reading one of our guru's posts here about the reasons why it is done like that. But the whole 'asset separate to material' thing bit me on the bum when it first appeared like many others.
My way to approach it is if I have to change anything or make a new material, I duplicate material. If I have to change anything in the appearance tab, I duplicate or choose another asset.