in both attached images the wall has a real world size material and if I copied that wall material, changed the color
and applied it to the decal object the result will be wrong as shown in the first image.
the work around was to convert the copied material to a normal material before applying it to the decal object which doesn’t make scenes! also I can’t simply apply a UVW Map modifier the decal object.
as I remember that was not the case before the last decal update.
Corona decals does not support real-world UV mapping yet. That’s not a bug, but rather a feature yet to be implemented. In your specific case i would suggest to utilize decal’s affect base rollout and uncheck the channels that you don’t need to modify (bump, displacement) and leave checked only channels that are unique to your decal (color, roughness?).
yes the work around was to disable “use real world size” option in every texmap in the material applied to the decal object and set the utiling and vtiling to 1
now it will appear correctly when projected on an object with real world size material
