Currently vcmi generates full zones underground. It is a temporary solution and IMHO it is in some way better/refreshing if one compares it to the way original h3 generator does underground.
So I’ve decided to post my opinion on it, in hope that maybe vcmi does a bit better job with rmg underground levels.
Problems with underground in h3 rmg :
-the underground is a desert (not too much things to visit / get … well at least a lot less then the surface)
- tunnels are complicated and often a dead end which makes exploration take lot of turns.
- almost no decoration (big mountains are never used for example), so we get boring tunnels without a single tree/forest/mushrooms… even though such graphics were made for h3
- almost every time I play rmg ends up making a big underground … as big as the surface. IMHO underground levels should be about 50% size of surface world max.
-Tunnels should be less cramped / wider to allow using some decorations/obstackles like forest/mountains etc.
-some regions could be a big caves (mainly those around castles) which would generate a zone like the current vcmi implementation does.
-it would be cool to have underground as a path to connect zones. Instead of teleporters place subterrain gates and one straight tunnel between them. Would be imho cool to have templates that would do just that instead of big underground levels.
-reduce the size of generated underground levels. Max 50% of the surface world
BTW original rocks/underground connections are very ugly in h3. h3 underground look more like some islands around void then actual underground, hence the current way VCMI rmg does underground is refreshing.
In my little legends projects since I was unable to make nice looking underground borders I’ve decided to do a lava terrain instead of rocks and a shore connections to normal underground level. What however gives the real underground feeling are the big obstackles (mountains) which look like underground cave walls . (See attached pic). So in my project if rmg works exactly as in h3, underground levels will be more like an empty lava world. The current vcmi way seems more interesting and maybe would be nice to have as an option to set in template. (fe. an option to set a percentage chance for rock generation and percentage of chance to generate mountains instead of rock terrain).