When I duplicate an object with Shift+D and then change color it also change the color on the original object. Same if I duplicate with Alt+D. I use Mac if that would matter. Would be happy for any help here since it is very enoying. /Peter
When you duplicate an object, by default the copy keeps the same material as the original. If you want to create a new material for this copy you need to:
- 2.79: Press U (Make Single User) > Object & Data & Material
- 2.8: Header menu > Object > Relations > Make Single User > Object & Data & Material.
In the case of a linked duplication (AltD), go in the Properties panel > Material > On the right of the material name click on the dropdown menu and choose Material, this way the meshes of the objects are still linked but not their material.