In addition to the above, also check out my fluid surface plugin, which involves creating and rendering a custom mesh. Also check out the CustomMeshComponent plugin that comes with the engine. And you can also look at my Metaballs plugin example.
https://github.com/Ehamloptiran/UnrealEngine/releases
Make sure your logged into your github account and that is linked to your UE4 account before you click on the link, otherwise you will get a 404 error.