If you already have a project and wish to use these assets in that project, it gets slightly more involved:
This scenario includes two projects: Your current project and an updating project (which will be used for updating assets)
- Download old assets (that contain Substances) into your updating project (older Unity version, i.e. Unity 2017)
- Update the project using Unity's project updating process to a newer Unity version (i.e. 2018.2)
- Import the Substance in Unity plugin from the Asset Store
- The assets should now be updated
- Right click the Asset folder and click 'Export Package' (make sure to uncheck the Allegorithmic folder, so you DO NOT include the Substance plugin
- Import the newly repackaged updated Assets into your current project
This does not seem like a good recommendation to make. I don't think it's a good idea to re-import your entire Asset hierarchy. It could take a very long time and also cause unexpected issues.
What I did was a bit different and much safer in my opinion. My steps (will only work in Windows):
1. Updated project from 2017.4 to 2018.2.14
2. Opened updated project, fixed any compilation errors in project or asset code
3. Imported Substance in Unity plugin
4. Closed Unity Editor
5. Made a copy of my 2018.2 version of the project
6. Searched the Assets folder (do NOT start from the project root, start at the Assets folder) of the copied project, using the search filter to only return files that do NOT have the sbsar extension: extension:~!sbsar kind:~!folder
7. Deleted all the search results so that only the sbsar files are left
8. Opened the copied version of the project that only has the sbsar files.
9. Exported a Unity Package of the Assets folder
10. Opened the original upgraded 2018.2 project and imported the Unity package to re-import the .sbsars
It worked, but not perfectly. I've seen the following two issues:
1. On some GameObjects connected to prefabs, the GameObjects were reset to the prefab state and the Substance Material failed to apply properly. There is no material assigned at all.
2. On GameObjects with more than one material assigned to them, the upgrade did not put the assigned materials back in the correct order.
And an enhancement request:
1. Please give the top level asset a custom icon so I'm not constantly confusing them with the fbx models