As described in About material types, you may want to replace your imported materials with Showcase materials to improve the look of your model and to have more flexibility and control over your materials.

To replace imported materials:

1. Select Appearance > Replace Materials.
2. The Replace Imported Materials window appears:
   
3. Do one of the following:
   • To run an algorithm that replaces materials for obvious matches, click Auto.

     The algorithm replaces imported materials with Scene materials if they share similar names. It removes spaces, colons and other special characters so that a name like "CarPaintBlueMetallic" is matched to "Car Paint::Blue Metallic."

   • To run a custom mapping algorithm, click Mapped. If the button is grayed out, no mapping algorithm has been defined; see Define a material replacement mapping algorithm. As files are found, the algorithm replaces imported materials.
4. Replace the less obvious matches or individual materials by mapping each one:

   Select an item from the Imported Materials column, click on its matching item in the Scene Materials column, and then click Replace to map them.