Our game has the following structure for items. In this example, I’ll use a Battery. (Like what you would use to power a flashlight.)
ItemParentBP (Base Mesh is there, but it’s not the root) → BatteryItemBP → item_battery_9volt
To make it look like the 9volt, we take the Base Mesh inherited from the parent and change it to that.
The problem lay there. For every single item we have, all of their thumbnails are using the base mesh in ItemParentBP, despite changing them in the child BP. This makes all the items thumbnails look the same (in our case, a can of soup.) It’s quite annoying and increases the time it takes to find our classes for our items.
There is no option to Generate or Customize Thumbnail when I right-click on the items.
Thank you for your report. This is currently a known issue, UE-7955 for reference. The issue is currently backlogged in our system, but I have added additional community interest and updated it with your information. As we investigate a solution to this issue, I will keep you informed here.
UE-17453 has a target of 4.12 for a fix, but a fix has not yet been submitted which means that this could easily get pushed to 4.13 if a fix is not submitted before we branch to start previews for 4.12.