Highway to Hell

monster's placement

Monster's spawning happens due to two different methods.
One is sort of random, the other implements certain monsters fixed to a place.

fixed implementation

Certain monsters spawn always at the same spot. 'Spot' should be understood as a part of a map, note that this part of a map doesn't need to spawn at the very same place in a map all the time. This applies to all Town Folks, Superunique Bosses, all quest-related monsters, and also to normal monsters in some cases. As an example, the latter allows Fallen Shamans (with assigned Fallens) to spawn always in Act1's Fallen Camps and ensures Catapults' spawning on their assigned places in Act5.

see also:

• Map Editing Board in Phrozen Keep

random implementation

Completely unaffected by fixed implementation (almost) every map will pick its population from an allowed assortment of monsters, most maps do three picks. This is controlled in Levels.txt via NumMon for monster class count and Monx for allowed monster classes. Keep in mind that some monsters will always spawn with their assigned minions, which is controlled via MonStats.txt; the density of individual groups is also defined here. So Fallen Shamans always will spawn with some Fallens nearby. Further rarity in MonStats.txt will determine the frequency of classes' spawning.
See also the Minion FAQtoid for details.
Entries in configuration data may vary for the three difficulties. Other mechanisms prevent a map from being populated with ranged attackers only.

Randomly generated boss- and championpacks are controlled via MonUMin and MonUMax columns in Levels.txt. Their monster classes are again defined via UMon in Levels.txt and rarity in MonStats.txt, for Normal difficulty. Higher difficulties will use NMon in Levels.txt instead.
So you may encounter Bosses or Champs of other classes than the 'three-classes-spawn-in-a-map' rule of thumb would indicate.

see also:

• General Mod Making Board in Phrozen Keep

survey

Let's take the Bloody Foothills in Act5 as an example. Shenk will always spawn at the same spot. His company is assigned to Shenk, so wherever he would spawn he'd have the same minions, which class is called 'Minion', too, just to annoy me while writing this. Dac Farren Superunique also always spawns at the bottleneck. His company is taken from his monster class, so he'll always spawn with Imps as minions.
Catapults are implemented into the map itself.
Two monster classes will populate the map randomly. In Normal you see common Minions (hmph) and Death Maulers, there's no other class allowed. In higher difficulties a variety of guest monsters is allowed, too, but only two picks will select population. rarity in MonStats.txt causes that annoying Burning Dead Archers to be picked rather more than other guest monsters. Just two picks are allowed, so it won't pick that Archers both times, since they're ranged attackers.

Monsters are activated in roughly two screen's distance to player characters and their minions; they commonly notice them in about half a screen's distance (this is part of individually assigned AI parameters and varies widely).

map generation

Most players only seem to be interested in how to very quickly arrive at next map without doing or receiving harm. Well, I myself never were interested in runs of any kind, so you won't find famous map layouts and 'tactics' to find next entrance here.
There is an illustrated topic by smartiie over at indiablo.de.

There's two ways of map generation. You see preset maps, which always look the same, and you encounter maze maps, which are randomly puzzled out.
To bring some fog into this some preset maps may be chosen from a set of presets, like Act1 and Act2 towns. Some maze maps will contain large areas which are preset or pick from a restricted amount of presets, like the lava maze part of the River of Flame map. Preset maps are

• Act1
  • Cave Level2
  • Forgotten Tower Level5 (two variations)
  • Inner Cloister
  • Cathedral
  • Tristram
  • Catacombs Level4
• Act2
  • Harem
  • Palace Cellar
  • Duriel's Lair
• Act3
  • Sewer Level2
  • Kurast Causeway
  • Travincal
  • Durance of Hate Level3
• Act4
  • Chaos Sanctuary (three variations)
• Act5
  • Nihlathak's Temple
  • Arreat Summit
  • Throne of Destruction
  • World Stone Chamber

Maze maps are hardcoded to some extend, so the entrances will match previous and next maps and important spots won't show up all within some paces' distance. Don't ask me about them, since I don't have a clue about it.

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Credits

• adamantine
• Myhrginoc
• Paul Siramy
• Red Havoc
• Ruvanal

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Contact me via E-Mail, if you like.

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