Revit 2011 additional render paths work differently with realistic views than with rendering
When you create a material with a custom texture outside the default render appearance library location the material texture is not visible in a realistic visual style.
In previous versions of Revit® you could specify additional render appearance paths for custom textures and decals. If Revit could not locate a custom texture it would then check the additional specified locations.
To specify locations for custom textures or decals navigate to R > Options > Rendering > Additional Render Appearance Paths.
In order for Revit to take advantage of the additional render appearance path functionality with realistic views, you have to add the path to the original texture before you assign the custom texture in the material or decal.
When you specify this location before assigning the texture or decal, Revit uses a relative path rather than an absolute path to the image.
Keep in mind this only affects views set to a realistic visual style. When rendering you can still use the previous workflow of specifying an additional render appearance path after assigning the custom texture or decal.