Full error message text:
Affecting only a part of a base material with a Decal material is only supported if both materials are Corona Physical Materials. Color, specular and roughness 'Affect Base' settings of decal(s) '<Corona Decal Name>' will be ignored.
Using the "Affect Base" feature of Corona Decal ( 3ds Max | C4D ) with Color, Specular, or Roughness options is possible only with Corona Physical Materials ( 3ds Max | C4D ). If any Corona Decal, in which any of those options is enabled, or any object, onto which such Corona Decal is projected, is using a different material type than Corona Physical Material, then this error message appears.
In the below examples, the Corona Decal object is using a Corona Legacy Material, which triggers the error message:
3ds Max:
C4D:
The solution is to either:
- Option 1:
Make sure that all Corona Decals and objects they are projected onto are using Corona Physical Materials. In this case all "Affect Base" options will be affecting any underlying objects' original base material properties as expected:
3ds Max:
C4D:
or
- Option 2:
Disable Color, Specular, and Roughness options in the problematic Corona Decal's "Affect Base" rollout. In this case, the Decal will not affect the underlying objects' base color, specular, or roughness properties.
Note: this error message may also appear when a Corona Light object is placed within the range of a Corona Decal's influence:
3ds Max:
C4D:
In such cases, the solution is to exclude any Corona Lights using the Include/Exclude button available in the Corona Decal options:
3ds Max:
C4D:
See also: Corona Decal at the Chaos Documentation Portal ( 3ds Max | C4D )