Sometimes you’ll run into a drawing where the object properties are set to a specific value, like a certain color or linetype, instead of BYLAYER. When you change the layer’s property, those particular objects don’t change. Sometimes that is what you want, but often it isn’t. Until now you had to manually go through and edit each of the object properties.
There is a new tool in AutoCAD 2008 that enables you to quickly apply the BYLAYER property to multiple objects, including those within blocks definitions. The new SETBYLAYER command is available on the modify menu. After selecting the objects you want to change, a Settings option enables you to specify which properties you want to be included in the operation. Additional prompts allow you to choose if you want to change object properties that are currently set to BYBLOCK and/or objects within blocks.