Material definitions are created, edited, copied, or purged in Style Manager. The Style Manager provides a central location in AutoCAD Architecture 2024 toolset where you can work with styles from multiple drawings and templates. Material definitions contain settings for the hatching, scale, and color of materials, plus rendering materials. You can find predefined material definitions in C:\ProgramData\Autodesk\ACA <version>\enu\Styles\<Imperial or Metric>\Material Definitions.dwg.