How to assign a parameter to a painted surface in a family

Here is how you can assign a material parameter to a painted surface in a family:

1. Go to Family Types dialog box
2. Add - Material Parameter
3. Paint
4. Choose the material that you made - it will have the suffix (param)
5. Done!  Save and load into project...

You can do this for multiple different materials on different painted surfaces.

This method was mentioned on the French 'Mastering Revit' blog:
Translated version of post

Original post
Revit mastering: Peindre