The “Action -> Export” is a legacy action (from UE3) which no longer does anything other than create the backend markup text for describing some assets (like blueprints and materials). It should be removed eventually because its not the proper way to ‘copy’ assets anymore.
The “best” way to move an asset from one project to another is to use the “migrate” tool. This will go through all of the asset dependencies and create a list of objects which need to be migrated in order for it to show up in your other project. IE, you have a material which has a texture sampler within the node network, the texture would get migrated as well as the material.
The worse alternative is to just copy the .uasset file from one content directory to another. Any dependencies would have to be copied over manually as well and any internal paths would have to be fixed up as well. There is a lot of room for human error here, so avoid this as much as you can.
If a uasset doesn’t show up in your other projects content browser but you see it within the content file directory, there are a few possibilities:
- The file is not compatible with the engine version (moving a uasset from 4.10 to 4.9.2 would not work, but moving from 4.9.2 to 4.10 ‘should’ work).
- The file is corrupted and there was some sort of error while the editor was trying to load it.
- You modified the engine source code (particularly “ObjectVersion.h” and the internal header data within the uasset is totally different from any of the ‘out of the box’ versions of UE4. This would cause any uassets to be visible within the modified version of the engines content browser, but not vanilla versions.
I’ve been in situations #2 and #3, with months worth of work at the risk of being lost. I managed to fix it, but it took about a full week and digging deep into the binaries of each uasset file and manually modifying certain header signature values via a C# script.
You’ll have to look at the cost vs. benefit ratio of recreating your assets from scratch (or a reference) vs. trying to hack out a solution like I did.
Also: Always make backups!