Hello to all who have visited this thread, this may help you out. (Possible solution)
Preface:
I had recently encountered a similar situation with my usage of Unreal Engine 5.1.1 where I was asked to update my plugin in the Epic Games launcher’s Unreal Engine “Library” Tab. The plugin For Twinmotion Content needed some minor update. I saw that my downloads section did indeed show a sub 500mb download. Great I thought since I had recently updated my Twinmotion to the latest release 2023.1 Preview 2 (as of April 12 2023). However, upon opening my project in UE 5 I was met with several warnings and errors. In my ignorance I pressed the escape key and I was then greeted with missing assets when everything was loaded. I noticed that all my trees were gone (they were painted via foliage tool but they were from Twinmotion’s Vegetation library) and the landscape also had missing texture. My grass and bushes stayed within the level because they were imported directly into my project folders via Quixel Bridge Megascans.
Investigation:
I checked in my content browser under the Engine > Plugins > TwinmotionContentContent. In the library there are missing folders and assets that were previously there. Therefore, I did some searching and was just getting unreasonable recommendations and this thread was the closest to see a discussion about this topic.
Failed attempts:
I tried the following to “fix” the issue. I went into my plugins settings and disabled, restarted, re-enabled, restarted again and same problem. Next I tried to uninstall all the plugins from the epic games launcher’s Unreal Engine Library section. I selected the current Engine and removed all 3 of the Twinmotion plugins (The importer, datasmith, and content) and reinstalled them all from the marketplace. Alas, this did not solve the issue. In frustration I even reinstalled the entire engine and again the plugins. I’m lucky to have fast internet without data cap. I feel sorry for those who have to redownload the plugin every time there is a problem and are asked to reinstall it and have to download.
So what now?
I decided to go and find where these plugins are installed when they are downloaded from UE marketplace. I found them in
InstallDirectory:\Epic\UE_5.1\Engine\Plugins\Marketplace
There I noticed something odd. There was the folder named TwinmotiontoUnrealBeta (This is the folder that shows up as “Twinmotion Content Content” in the editor within the content browser) and this folder has the missing assets within it. In the engine and the install directory. So even if I use the function of validation by right clicking the folder and pressing the “Validate Assets in Folder” I do not see my missing assets and the console gives me a “Success” message with only some 400 ish assets scanned. However, the folders are also missing in my file explorer.
Solution - My Eureka moment:
I had noticed that in my plugins folder within the file explorer was another Twinmotion content folder that was the one that actually had all the content that was missing from the one in the engine. The name of this folder is “TMtoUEContent” and inside it are the same exactly named plugin files “TwinmotiontoUnrealContent.uplugin”. I was out of ideas so I thought “what the heck, let’s see how this goes” and I copied all the contents from the folder TMtoUEcontent to TwinmotiontoUnrealBeta. This was done while the engine was closed. I did not let windows overrite old data incase I may have corrupted the directory. I started the engine again and I felt some excitement when I saw the missing folders now appear in the Engine>Plugins>Twinmotion Content Content (in the content browser). I re-ran the the validation function and the engine took some time to recompile the assets (Mesh fields, Shaders, textures etc.) and decided to place a tree mesh by simply dragging and dropping. Finally, the mesh was successfully placed into my scene and it has all of it property as it should (Textures, animation, materials, everything). Thus, I had my Eureka Moment.
Conclusion:
I’m just an Architect who is trying to create his ArchiViz Company. I don’t have much experience with Unreal Engine. I started using it since February of 2023 and I love this software for it’s capabilities. I hope this message gives the reader a possible temporary fix to the problem. I did try to import the twinmotion content into my project folder but that broke all the meshes (missing information regarding material, texture and no animation) so I would not recommend it for anyone who is a novice like me. I just threw all my ideas because of my desperation. I managed to finally fix this issue for me. I hope others are able to work their issues out too. I spent 3 days non-stop searching for answers and I hope those who stumble across this have their downtime shortened.
Cheers guys,
some ArchViz guy