{world}/Terrain_{tile}
(literally including the curly braces). In this tutorial at around 5:25 Simon edits the Level Path parameter leaving the {tile} in curly braces. The Level Path parameter seems to evaluate an existing @tile attribute and append it to the Level Path. So the Level Path parameter:
/Game/Tutorial_Scene/Maps_Desert/Tut_Terrain_{tile}
Adds the existing @tile attribute to the resulting @unreal_level_path attribute. He gets (presumably, not shown in the video):
@unreal_level_path = /Game/Tutorial_Scene/Maps_Desert/Tut_Terrain_0 /Game/Tutorial_Scene/Maps_Desert/Tut_Terrain_1 /Game/Tutorial_Scene/Maps_Desert/Tut_Terrain_2 .. etc
With each @unreal_level_path attribute being composed of the @tile attribute and the Level Path parameter. However, if you open the WorldComposition Prepare node and look at how the @unreal_level_path attribute is defined, it is just a line of vex that points directly to the Level Path parameter.
I have never seen this curly braces syntax in Houdini before, is this an hscript global variable or something? When I use the node as described (inputting a tile split terrain with @tile attributes), it literally adds {tile} to the @unreal_level_path attribute, so I get:
@unreal_level_path = /Game/Tutorial_Scene/Maps_Desert/Tut_Terrain_{tile}
... for all tiles. How do these curly braces work?