Download the mesh.
Unzip the download. (winzip, 7zip, or winRar required)
From the new, unzipped folder, take the following files:
-.mesh
-.material
-.png/jpg/gif/etc
Move them to the feralheart folder "my_objects".
Load the game.
From tools, go to object maker.
Second tab. Meshes.
In the first text box, type the file name of the mesh. (ex: waterfall1.mesh)
Spelling, capitalization, and punctuation are important.
Hit the "add new" button.
Suddenly, new mesh appears.