[Guide] From rolling ancient tunnel maps to completing the grail

Albatross

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Apr 27, 2009
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It's well established that Pit Zerkers are the kings of magic find. The SPF Hall of Records and recent Magic Find Olympics will attest to their efficiency, yet some still prefer an Ancient Tunnels (AT) sorceress. That might be because of play style, an affinity towards spells, or a tendency to go with the underdog. However, @Owlie's new magic find efficiency spreadsheet, which factors in the number of minion and regular monster kills, indicates that the gap isn’t as wide as was once believed. Another reason to play an AT Blizzard sorceress is if you have just (re)started as they are much more forgiving gear-wise than Pit barbarians.

Table of contents:

I. Cartography
1. Map Variations
2. Map Density
3. Map Assessment
4. Shrines

II. The Blizzard Sorceress
1. Stat and Skill Distribution
2. Equipment Milestones
3. General Gameplay Tips

III. Further Improving Run Times
1. Keyboard Shortcuts
2. Inventory Layouts

IV. Miscellaneous and Speculative
1. Improving Save and Load Times



I. Cartography

I've searched far and wide, but couldn't find any in depth information on AT. This was my main motivation for writing a guide which focused on rolling and assessing maps.


1. Map Variations

Rolling a good map can be both time consuming and sometimes frustrating, even more so if you aren't exactly sure what you're looking for. I've had this issue for a long time and decided to explore the subject thoroughly, hopefully learning much in the process. Although I haven't found all the answers I set out to unravel, I've made some interesting and useful discoveries. I hope they prove valuable to you as well.

Through my research, I've established that AT maps can consist of a varying number of rooms. This number ranged from 10 to 12, and I found each as likely to be rolled while examining more than 50 different maps. The collected data also indicates that spawn density does not correlate with map size, making the "10 room" maps most likely top contenders. I've come up with a naming convention for maps by counting the number of rooms and their "square area", which is basically counting the rooms on both axis and multiplying the results. However, the number of rooms alone is not enough to predict a map's success, their layout should also be taken into account. Before continuing to ramble, I'll include an example as it should make things much clearer.

Featured is a "11-12 type" map, it has 11 rooms aligned in a way which almost form a square (4x3):
AT map 11-12 6.21.jpg

The observed map area never exceeded the 12 to 30 square range and likely cannot due to the maximum room count and the way segments have to fit together.

In my experience, efficiency wise, the tightly packed maps performed better. Simply because everything was much closer together. However, a spread out map's spawn patterns may make completely ignoring large sections of it possible, thus making it competitive. This falls under the area of density distribution.


2. Map Density

Now we know a bit about map layout, but still need to determine how to properly assess map density.

Contrary to what you might find in various wikis and forums, the actual number of unique bosses or champion groups (packs) in the AT is not 6-8. No matter how you count the mandatory spawn near the chest. The actual number, chest spawn included, is 3-9 and varies from map to map, reliant on unknown but consistent game mechanics. During map assessments, I've seldom come across maps which could spawn 9 packs, while several sometimes rolled the minimum of 3.

At some point, I've actually started extracting and documenting individual rooms. Although I've stopped this direction of research, I've concluded that there are no more than 30 unique segments which comprise an AT map. I've sorted the rooms by the orientation of the hallway(s) and started noting the average density each one produced on different maps. I've stopped in the middle of updating my marking scheme as I've come to the realisation that there's nothing special about individual rooms. This was easily observable in instances where one room would be very rich in spawns on one map and really poor on another.

Individual segment catalogue (incomplete):
AT segment catalogue.jpg


The exact mechanics appear to be unknown and I've come to terms that I'll not be the one who discovers the inner workings behind density distribution. This might have been uncovered at some point, and lost in the void that is the Internet, and may yet again be revealed by code diggers.

And that time has come! @Fruit brought to light those exact inner workings. I'll start with an image and explain what's going on.

AT 11-16 combined.jpg

This is what happens when you go down the drain:
  • the area around the entrance (red) will never spawn anything to prevent stair traps, in AT at least... and it's about the size of the segment
  • as soon as you jump in all segments adjacent to the one you are in will be populated with monsters and some of those monsters will be upgraded to uniques (80%) or 1-4 champion groups (20%)
  • when you cross the border of another segment, all the segments which are adjacent to it will be populated
There are two important variables which control the spawn upgrade process: segments_spawned and total_segments. As shown in the image segments_spawned will increment for each segment which is adjacent to the entry point. After each increment the upgrade check function is called for each group of monsters which were spawned in the segment:
  • segments_spawned * 100 / total_segments
The result is compared to a random roll 0-99 and if it's less than 20, a group of monsters will be upgraded to uniques or champions. It's still unknown in which order this plays out, but let's take a guess and say segment #4 would get upgraded first.

segments_spawned will equal 2 (because the initial segment is also counted), while total_segments is 11 for this map.
This gives segment #4 18,18% change to upgrade any of it's spawns. Let's assume segment #5 is next. The following would apply: 3 * 100 / 11 = 27,27%, etc. This will continue until the minimum upgraded monster count condition is satisfied, which is 4. Afterwards, a simple 6% chance is applied to each consecutive spawn until the maximum count reaches 8. The maximum count does not include the mandatory chest spawn, this is why some maps are able to exceed the cap and give 9 packs. It's also very important to note that each champion counts individually. So not only are their drops worse, but they'll eat up the maximum possible upgraded packs and there's nothing we can do about it.

With all this in mind, I drew the following conclusions:
  • the starting room can't spawn anything
  • a single room can spawn up to N packs, but anything above 5 is exceptionally unlikely (I've never seen it happen)
  • the chest room may spawns next to nothing, barring the default pack (unless it's bugged and fails to spawn it)
  • champions spawn instead of uniques 20% of the time, confirmed both by my findings and the Amazon Basin Wiki
  • a map can spawn no less than 3 packs (chest spawn included)
  • a map can spawn no more than 9 packs
  • maps which have their chest room adjacent to the entrance will never be able to spawn 9 packs because the upgraded monster counter is "wasted" on the mandatory spawn
  • it's still not necessary to finish your run with the chest room, just avoid spawning it for as long as possible to have the best chance of reaching 9 packs
I'm still fairly certain that 10 segment maps are superior because they have a greater chance to "burst spawn" up to 4 packs early in the run, hitting another 2-3 before the chest room shouldn't be uncommon. Having several packs in one room does wonders for efficiency and you'll want to be able to reach the maximum number with as least segments visited as possible.

3. Map Assessment

With all of this information we should be able to confidently assess AT maps. I've developed a process which should make this as painless as possible while also making sure you do not re-roll a good map in not knowing any better.

The first step is to roll the best possible Rouge Encampment layout and Lost City waypoint, bonus points if Cain is not inconveniently placed behind the hearth.

Ideal Rogue Encampment layout:
Act I WP.jpg

This type of map makes it possible to access the waypoint with the least amount of walking, using Telekinesis from the position shown in the image. Cain's location is important if you do not rely on manually identifying items, but do so after a run. The distance from the Lost City waypoint to the trap door can be as little as one teleport, while this is ideal, 3 should be perfectly acceptable. Another thing to note is that you should favour maps which do not require you to teleport to the south. Since the user interface is organised in a way which obstructs a part of the screen teleporting southwards will usually be less efficient than going north, while east or west is preferable to both because more screen space is available horizontally.

Finally, we come the AT map itself. As mentioned earlier, a dense layout consisting of 10 rooms is likely going to come out on top. Ideally, your first teleport will take you to a room which has the first spawn so you'll spend as little time as possible from starting a run to killing the first pack. If you decide the layout is acceptable, take a screenshot of the minimap and enlarge it, then draw a grid over it. It may seem daunting at first, but you'll quickly realise that it's only difficult to make a mistake. This is because the game handles the rooms exactly like a grid. I've easily managed all of this in Paint, it should be a breeze with a superior tool.

Drawing a grid:
grid drawing 3.jpg

Enumerate the rooms the way you are most likely going to be running through them as this should make the assessment process easier. When done, you can actually do some runs! I found it about the same time-wise to record a video of my runs or to tab and note the packs as I go. Both methods take time and are prone to errors, but those should even out when working with a larger sample size.

Documenting runs:
collecting results 2.png

10 runs should already be a good indicator of what you're dealing with. If the map's chest room is adjacent to it's entry and it spawns only 3 packs more than once (chest pack included), you should reroll. A map with that type of layout probably can never spawn 9 packs. Once you've documented 20-30 runs check the average density, if it is below 5.5, you should look for another map. Your goal is to find one which will spawn 6 or more packs on average. All of my maps, which had an average density of ~6, were not below the 5.5 mark even after just 10 runs. 20 runs were usually enough to accurately predict the final density score.

Once you've documented a 100 runs, calculate how many packs each room spawned and add this information to the grid. This will help determine your run route which will hopefully resemble something like the following image.

In white, the percentage of pack occurrence, while yellow stands for pack % with the chest spawn excluded:
AT map 10-15 6.06.jpg

I though that this was a very good map, but I know better now and no longer regret rerolling it. A "10-15 layout" with three completely irrelevant rooms, and an average density of 6.06, likely in the 1.95 Fabian's range. There were no dead ends you had to visit and no need to double back. The ideal path, though a bit difficult to pull of correctly, would have probably been clockwise, visiting the chest and hitting the high spawn rate rooms first. Unfortunately, the chest room would get spawned the moment you entered the dungeon ensuring that the map would never be able to upgrade 9 spawns.

You don't necessarily want the chest room to be at the end of the run, but you certainly don't want it to spawn early. Try to find a path which will spawn at least 4-5 rooms before the chest room is in range. During focused runs, you can count the number of packs you kill and see if you reach the maximum or maximum -1 your map can spawn by clearing only 2-4 segments, then save and exit immediately. This way no time is wasted teleporting through empty rooms just to reach the chest pack.

When you are satisfied with the map's layout, density, and "feel", the only thing left is to time your runs. The ultimate test will vary between maps, individuals, depends on the hardware you are using, some software to make this game run smooth in 2018., what you ate for breakfast, and the alignment of the planets... As rule of thumb, a 40s run with an average density of 6 is already an excellent result and will, on average, net a Tyrael's might in 745 hours, when running with 500 MF.

Remember that it takes a lot of practice to efficiently run a map. My first "official" go at this map clocked in at 38s per run and it took 3 more 100 run batches to bring it down to 31.5s, which would likely improve if I'd continued running the map.

Here's a quick summary of what to look for:
  • best Rogue camp layout, 1-2 TPs from act II WP to entrance
  • 10 rooms
  • the chest room is not adjacent to the entry point room
  • the layout allows not spawning the chest room early in the run
  • 4 minimum spawns
  • 9 spawns are possible
  • full clear density is >6
  • almost no double backing
  • 1-2 shrines, both on route
  • the first boss is only 2-3 TPs from entrance
  • the chest room is not the final room you visit
Here's my best AT map to date (of course I rerolled it and never found a better one):
  • best Rogue camp layout, 2 TPs from act II WP to entrance
  • 10 rooms, of which 2 spawn very little
  • 4 minimum spawns, 3 might be possible, but incredibly rare
  • 9 spawns are possible, but also rare (1-2x / 100 runs)
  • full clear density is ~6.37
  • almost no double backing
  • 2 shrines, both on route
  • the first boss is only 3 TPs from entrance
  • the chest room is not the final room you visit*
* this means that I'll check room #10 only if I kill <5 bosses before I reach the chest. This improves run times without sacrificing density.

Still, there are downsides. Like spawning stuff in tight tunnels, mostly room #4. Those are difficult to kill with blizzard and slow me down. Also the first pack, which is present in almost every run, is behind a pillar and I have to guess where to shoot to kill it. Therefore, I believe an even better map is possible, but I wont be re-rolling this one any time soon :)
AT map 10-20.jpg


4. Shrines

I could barely find any mention of them in regards to MF runs so here are some bits I've gathered:
  • an AT map can spawn up to 4 shrines, possibly more, as shrines come built into rooms
  • of those which had 4, only 3 were "interesting", the 4th was either a health or mana shrine
  • no wells spawn in the AT
While rolling a map, one should also pay attention to shrines. Especially when starting out, they can be of great use. Removing a curse and regenerating your life or mana will reduce your potion consumption and pickup, making you more efficient. Some players will also find experience, skill, and gem shrines to their liking. Additionally, blowing yourself up with a fire shrine is always an option :)

I jest, but even though a fire shrine can't kill you as it only halves your health (rounded up) it may easily contribute to casualties. So be careful when activating, but you should still examine those unlabelled because they might roll into monster shrines which produce either a unique or a single champion if there's a normal monster nearby. Although I cannot attest to their drop odds, the converted monsters should be fully capable of dropping TC87 items. However, you should also take into account that successful upgrades from shrines increment the total packs count and can actually lower your overall density, unless you use them after you've activated all of the segments you'd normally run. This could make a "10 pack" run possible.

As interesting as shrines may be, you should also learn to ignore them most of the time. Only activate the ones you need, when you don't have to go out of your way to do so.

This wraps up the map rolling section of the guide. Coming next are guidelines on improving your AT runs.



II. The Blizzard Sorceress

I'm not a hardcore player and you'll probably get your sorceress killed following my advice, as I do, frequently.


1. Stat and Skill Distribution

If you are just starting out, Shiver Armor could be of use, but should be replaced by Battle Command and Orders once you make Call to Arms. The rest of the skills are to be distributed so that:
  • 1 point goes into Warmth, Static Field, Telekinesis, and Teleport
  • 20 points into Blizzard and its synergies
  • and 20 points into Cold Mastery
Spare points can be used to further boost Ice Blast damage trough its Frozen Orb synergy.

Playing with runeword mode? You'll want Spirit, so that's 156 strength, usually 144 when factoring in Harlequin and War Traveler's stat gains and the rest goes into vitality. No RWM? Using the alternative equipment setup below, you'll need at most 93 strength to use the War Traveler boots.


2. Equipment Milestones

You can run AT with pretty basic gear, but there are a few difficult to obtain items which will dramatically increase your efficiency. The first one you'll likely manage is a Call to Arms, by the time you have one or can cube an Ohm rune, you'll probably be close to having a Tal Rasha's belt, armor, and amulet. The final piece of the puzzle is a Death's Fathom. Until then, use The Oculus if you can stand the random teleportation, while Heart of the Oak is a nice alternative if a Vex comes your way.

Your mercenary can get away with a plain Colossus Volgue Insight and anything for the armor and helm slot, but an ethereal GPA Insight, AP Fortitude, and a Chamed Andariel's Visage will make him both unkillable and very efficient in dispatching cold immune uniques.

The biggest difference will you run with 63 or 105 FCR? 105 FCR is going to be slightly faster, at the cost of MF. It also feels a lot smoother. Here's an example 63 FCR setup:
  • Harlequin Crest (Perfect Topaz or Ist)
  • Tal Rasha's Adjudication
  • Tal Rasha's Guardianship (Perfect Topaz or Ist)
  • Tal Rasha's Fine-spun Cloth
  • Death's Fathom (Ist rune)
  • Chance Guards
  • War Traveler
  • 2x Fortuitous ring of Fortune (or 2x Nagelring)
  • Spirit x2
  • Call to Arms
  • Gheed's Fortune
  • The Horadric Cube
  • 33 small charms with MF, resists or other prefix
  • if running with 63 FCR, I'd recommend sacrificing one MF SC to reach the next FHR breakpoint
After tens of thousands of runs, I've come to the conclusion that 105 FCR becomes better as your gear progresses. While there are diminishing returns on magic find, you'll always cast each spell 0.04s faster with 105 FCR, compared to 63 FCR. This might seem a minuscule amount, but considering that at least 50 spells are cast during a run the total saved time would amount to 2 seconds.
Maxing lighting resists shouldn't be an issues since the gear's got you covered, but cold resists should also be as high as possible to avoid situations like this one.

A very dead sorceress:
dead.jpg

Just look at that thing, creeping around with a sliver of health. A Cold and Lightning Enchanted unique with Conviction will blow you up before you even realise what's going on. Blizzard will frequently put such a monster into hit recovery and each time this happens the boss will emit an invisible Frost Nova which also carries lightning damage. And if the monster is cold immune, your mercenary will happily put it into hit recovery for you.

While a vanilla player's gear choices are somewhat limited, it's still possible to be highly efficient. The biggest difference is in not having access to Insight, but you can work your way around it by playing more careful as to not get mana burned as often. Unfortunately, I doubt a 105 FCR setup can come out on top without the RWM so you'll have to do with 63.

The best substitute for Spirit is Lidless Wall, most likely socketed with an Ist rune to offset the MF loss. Trade one Nagelring for a Stone of Jordan and the other for a FCR ring, preferably with mods like +strength, mana, magic find, resists. Insight should be replaced with a Reaper's socketed with a Shael or IAS jewel, if using a Chamed Andariel's, and Fortitude with Treachery.

I've briefly tested this setup on my latest map and it wasn't that far behind the one with RWM.

3. General Gameplay Tips

Hold down the "highlight items" key while teleporting to avoid getting stuck, and while casting Blizzard. Pit Zerkers may be mechanically difficult to play, but once you master the routine they and their skills are completely reliable. Blizzard however, never is, but you can make the shards hit sooner, or hit at all :p Avoid name locking and aim slightly to the side and below your target. By courtesy of @Fruit I've learned more about the spell, and it turned out it's a bit more reliable than I thought.

Blizzard is an area of effect spell which deals damage over time, but has a casting delay. Its massive damage, listed in the skill description, is per shard. Ideally, you should kill most packs with the first few shards, but this takes a lot of practice.

While individual shard x-coordinates are random, there are only 3 y-coordinates where shards land. This is best observed in Fruit's test.

Blizzard shard pattern:
blizzard pattern.jpg

As far as I can tell, it doesn't matter in which direction Blizzard is being cast. The "y-lines" are always at this angle. This is probably what Blizzard sorceress players already instinctively figured out and are using it to aim.

When you get comfortable with aiming, you should also use Blizzard's timer to your advantage. Not being able to cast another Blizzard does not mean you are unable to teleport or shoot Ice Blast and Glacial Spike. Use the time to either explore the adjacent room or engage another pack. With enough practice you'll essentially be killing two packs at the same time, instead of waiting out the timer. Even if Blizzard doesn't kill the boss, it's bound to get at least some damage in and most of the minions will probably be dead making it very easy to finish the pack when you TP back to check the drop.

Once Ice Blast reaches ~2.7k damage, it can reliably 2 shot skeletal mages. This plays very nicely with casting a Blizzard on a more sturdy pack and then telebombing the mage.

Use telekinesis to activate the Act I waypoint. You can also open the AT trap door with it, but I don't find this useful because you can never be close enough to do it without moving first. If you are picking up gold (you shouldn't) also use TK, as well as to replenish your purple potion supply.

Remember that each mob should be approached differently, depending on its AI:
  • mages will try to run away from you, so either take them out from a distance or telestomp
  • raiders have the most hit points and will quickly close in on you, but are also large and the easiest to hit with Blizzard
  • the two fleshy undead behave similarly and will engage at a leisurely pace
  • try to eliminate champions as soon as you see them because they will scatter if left unattended
  • help your merc deal with immunes by killing everything else with your spells and use SF to lower the boss' HP
If you miss a Blizzard because the monster quickly engaged or fled, teleport behind to make them run back into the shards.



III. Further Improving Run Times

Still reading? Ok then, here are some tips to further boost your efficiency.


1. Keyboard Shortcuts

If your are still using the default key bindings or, gods forbid, the mouse wheel to cycle through skills (like I used to until recently) consider improving your efficiency by rebinding the default keyboard shortcuts.

Most people have their own preference, but a common approach is using QWERT and ASDFG for skills. Also remap the item highlight key from Alt to Space to avoid agitating your carpal tunnel.

It can take a long time to get used to the new keys and might feel terrible at first, but it gets better as you do more runs. Once you get used to them you'll never want to go back.


2. Inventory Layout

There are several interesting configurations, depending on what you want to pickup. If you like to check out circlets and jewelry, ID some rares, you should definitely go for 8 empty slots with an ID tome, might even add the cube for extra storage. This setup is more appropriate for a relaxed format, at the expense of having less MF.

Once I hit grail -4ish, I've switched to "cube runs" where the whole inventory is dedicated to MF charms. I keep 4 ID scrolls in the belt for emergencies, like when a Gheed's drops. The rest of the items I still pick up (grand and small charms, grailers, TC87 and highly sought after uniques, high runes) are tossed into the cube and dumped to the stash on the start of the next run. Another advantage of not having an inventory is that you can't accidentally pick up junk.



IV. Miscellaneous and Speculative

Haven't had enough? Guess it's time to make your runs supersonic.


1. Improving Save and Load Times

Having a modern computer with an SSD will definitely improve these. There are a few more tricks though, which I'll separate into:

a) definitive
  • use Sven's glide wrapper, tweak the settings and check how they effect the game, rinse and repeat until satisfied
  • if you think you and your eyes can handle it, play in native windowed mode, there's nothing faster than this
  • use the -ns (no sound) command in the shortcut, playing without sound makes the game load faster
  • take advantage of keyboard shortcuts for confirming character selection (Enter) and selecting the difficulty (H for Hell)
  • screen rendering has a delay and you can "blindly" interact with the interface saving miliseconds
  • .map and .ma0,1,2 files grow large, they can also cause slowdowns, these are safe to delete (but backup first, please) and only effect the character's minimap
b) speculative
  • giving the d2.exe process a higher priority in the task manager, also assigning only one core might also make a difference, but it's unlikely
  • I've seen reports of RWM causing slow saves, try removing -direct and -txt from the shortcut when you don't need RWM
  • having a ton of characters on the starting screen can slow the game down, try moving them to a separate folder during intense running sessions, also useful to prevent accidentally entering the game with the wrong character

In the end, remember it's all about the journey... or something along those lines...
sacred.jpg

I'd like to thank everyone who I pestered with questions and bounced crazy ideas off while working on this guide (
@Fruit, @GalaXyHaXz, @Owlie), as well as the whole SPF community for what it is and stands for. I hope we all find our Tyrael's in the end.

Created: Oct 29, 2018
Edited: Aug 3, 2019
Moved: Apr 5, 2020
 
Last edited:
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Moving some of the discussion over, there's really good stuff in there :)

Cleaned it up a bit.


First mention of "spawn patterns" by BeLikeLebron.
BeLikeLebron said:
I forgot to label a room in the middle (which I'll call room #12). That room I don't actually visit but kill bosses that spawn on the edge of room 8 as that's where the nice boss spawn is usually at. So three gem shrine possibilities in total per run is already nice - 2 in AT one outside of AT door. Of the 12 rooms I typically visit 8 rooms - I say typical because theres a exception route which I decide to take or not in room 4 (see red arrows). Three of the rooms I couldn't find in your Individual segment catalogue of rooms - the entrance room tile #1 and room tile for room #6 and room #3. After about 300 runs I came up on a decent route for teleporting and know pretty well where the bosses tend to spawn. Of the 3 boss spawns in rooms 2/3/4, If there is a boss missing, I take the longer route to visit rooms 5/6 instead of skipping them. That's because if there is no boss in rooms 2/3/4 there is generally 1-3 boss packs in rooms 5/6 from what I've noticed. Rooms 5/6 almost never has bosses when one of the other three rooms spawn a cumulative 3+ bosses but usually spawns bosses if there are less than 3 on the way there so there is probably some sort of pattern that happens. The boss pack in room 7 is killed in both routes if he's there.

Albatross said:
@BeLikeLebron hello again and thanks for taking the time to put my guide to the test :) I'll go right ahead and answer your questions.

1) I've noticed patterns, but more in line of, if I haven't found at least 4 boss packs (and there were no champions) they have to be somewhere. This is when I check the final room on my map, which I'd normally skip. If there's nothing there, I know that they've most likely spawned in one of the rooms I skip. However, even with some certainty I'll find 1-3 packs there, on my map it's simply not efficient to take the gamble and look for them. Looks like this is more apparent on larger maps and may be key in running them effectively.

2) When you time the runs you'll have more information, but I think you can do better map-wise. I feel there's too much space to cover for the density it provides. I don't think you've mentioned your last map had 6.4 density, I'd still be annoyed by that chest spawn though :), but I'd also bet it was more efficient than this one.

So... I'd reroll. It's hard to estimate how long it took me to find mine, but I think I assessed at least 10 maps before stumbling upon the current one. For comparison, Corrupted said he found his in 15 minutes...


A little exchange about counting AT packs and a reminder to use the Talk to Warriv -> AI -> AII -> AT route.
art_vandelay said:
@Albatross So if every individual champion counts towards the bosspack limit then what if during your 20 (or whatever) test runs where you count bosspacks you get an unusually high amount of champions and you trash the map because it has 'too few' bosspacks?

In fact any amount of champion spawns greater than one could ruin the count we are most interested in: # of regulars upgraded to champion/unique

This probably means that the only way of finding the true amount of bosspacks possible on a map is to only count runs without champion spawns. I.e. finding a map becomes this:
  • Look for a good layout (as described in your update above)
  • Count bosspacks on all runs without champion spawns.
  • Also count number of champion + unique packs (i.e. champions not individually) on maps where champions spawned but the maximum number of bosspacks is not reached (for that criteria we count champions individually though)
  • Keep if those numbers are high enough on average
This would be an absolute pain since the chance for a champion pack is still quite high.

Albatross said:
@art_vandelay I've gone through the same thought process and came to the following conclusion. It's still somewhat painful, but not as bad.

You count champions individually and divide the number by 2.53 to get a unique equivalent, then add the number to the uniques total. See my latest spreadsheet for an example. I've also experimented with minions counts in this sheet, but this varies wildly so I've just used 3.5 per unique as approximation. Unless my math is way off (which is very possible :D) this should be the most accurate method of determining density and counting killed uniques/champions in the way we are interested in.

There's one more thing to mention about unique/champ count, it's possible for a map to exceed the limit, depending on the order of upgrades. Best theoretical scenario: the map upgrades 7 groups to uniques and the last attempt yields 4 champions, with the chest spawn you'd hit 12 total, laughing at "MonUMax"'s value of 8. As long as the total number is less than 8, the map will attempt to upgrade a spawn, but wont cap the champion count. Anyway, the highest I've seen was 11.

I also have a feeling there's some interaction between monster shrines and the count, but not in a way which would benefit runners. I'm still far from drawing any real conclusions.

@Bukama
You go back through the AT entrance to the waypoint and jump to act 4? That might work on some maps, but I doubt it's faster than save & exiting in AT, then talking to Warriv in the new game to go to act 1 where you are a few steps and a TK from the waypoint.

Edit: here's an example, the linked video starts a few seconds before I finish the run and S&E. Then start a new game, talk to Warriv and port to Lost City from the Rogue Encampment WP.


@Kefir-Tribe's good questions.
Kefir-Tribe said:
I don't quite understand the explanation of the algorithm here. Is it the result of the formula segments_spawned * 100 / total_segments compared to a random roll of 0-99? If so what does "if it's less than 20" mean? A comparison would return a boolean true or false.

Are you saying the upgrade check is run on all groups of monsters in one segment before it moves on to the next segment, or does it perform a first check in one segment, jump to the next, then jump back if there are no more segments, etc.?

When the player moves to a new segment, does segments_spawned keep being incremented, or is it reset and then incremented as the upgrade check works on segments adjacent to the characters new position?

If I understood it correctly, the percentages in the map indicate "out of all boss packs spawned during test runs, x% spawned in this room". Why did you choose this statistic? Could an alternative be to calculate average number of boss packs spawned per run in each room?

When collecting statistics on a map, do you follow exactly the same path in all test runs? Do you think it is worth collecting statistics on several different paths if the layout allows, or is it better to just traverse the rooms using the most efficient path and reroll the map if the results aren't good enough?

Isn't there a risk that skipping "unproductive rooms" could tilt the upgrade check algorithm to roll less boss packs in the good rooms?

What's the motivation to not visit the chest room last?

Is this to avoid name locking things with teleport?

Finally, what player setting do you recommend running on?

Albatross said:
I should probably reword that bit, it was written in a hurry. This is what I believe happens, but can't guarantee anything since I've never gone through the code and am only interpreting Fruit's findings.

You go down the drain and all adjacent segments are spawned. Next, the regular monsters are randomly positioned throughout the segment. Checks are performed on tiles, it's possible we can to some extent influence this distribution by taking different paths. Upgrade checks go next, segment by segment. This is where the segments_spawned * 100 / total_segments formula applies. The 20 in the less than 20 part is an example value if only 2 segments were spawned on a map with 10 segments total. The game rolls a random number between 0-99 and if this number is lower than segments_spawned * 100 / total_segments a pack will get upgraded.

The segments_spawned never goes down and the upgrades should go segment by segment, no skipping.

Sure, a different approach can work, as long as you know which rooms are valuable and should be in your path. Knowing what I know now about AT, I'd probably just stick to "heat maps". It will tell you more about where you should move.

Yes, I test run the map a bit and try to find a nice route. Test 50 runs, then try another 50 counter-clockwise or slightly different path, if the map shows promise in the first test. The risk is rather low once several rooms are spawned, besides your aim is to "force" spawns on the route you take by avoiding to trigger too many rooms. If there's some spawn happy room, but it's really out of the way you'll probably be less efficient by clearing it than skipping it.

If you don't normally end your run with the chest room, there's a chance the map will spawn max or close to max by the time you reach it. You can save & exit immediately after that and ignore the segments you'd normally check after the chest room. In the long run, this will make your runs more efficient.

Yes, it's annoying and slows you down.

P1 for shiny stuff, P+ for exp if you like AT. There are better places for a blizzard sorc to level up, if that is you goal.

I don't have access to my game at the moment, so here's a really bad drawing instead. I think it's easier to explain all of this with an image so here's one type of map I consider "ideal". From entrance to chest room, you won't trigger any rooms out of your route and by the time you reach the chest there a very high chance everything that could have spawned already has in those 7 segments. Of course, if you encounter and kill 6-7 uniques when you reach the chest, just S&E and skip the remaining 4.
good at map in paint.jpg

An even better map wouldn't even have the segment where the arrow ends. It would leave you with 6 rooms to spawn stuff, which should be enough for max and likewise, only 6 segments to check. A map which seems to spawn very little in that same room would also be great.


Thoughts on resists.
drmalawi said:
Do you all guys run Blizzard Sorc in AT with negative resistances? (or what kind of resistances do you get / aim for - also how much health to you aim for)

Albatross said:
I aim for slightly stacked lightning and at least 50 cold resist. Overkill most of the time, but then you get those rooms with LE/CE/conviction and it gets ugly when they start blowing up. Fire and poison res are around 0, fire being the least important.

With decent resists you can get away with less life. Mine had 1800 after BO, which was enough to survive the occasional amped might hit or two before teleporting out.

Without Tal's you probably need high end MF charms with lightning and cold resist.

Gripphon said:
As for resists in AT, I consider poison to be valuable to have otherwise there is the need for drinking an extra potion per run and spending more time picking them up. While less important than lightning and cold, I make sure to have good poison resist to ignore drinking potions and picking them up due to poison damage. It does influence speed of running too. Still, it is an option if player can afford it due to available charms.

As for 1.07 bases, they aren't relevant for anything except maybe Singer barb and whatever else relies heavily on merc damage output.


ffs' take on gearing and damage.
ffs said:
I guess this is a good place for some AT Blizzy questions. I somehow finally got rid of the horrible ~5-10 second lag I experienced whenever I went Warriv => A1, which prevented me from giving AT running a serious shot so far.

So the last couple of days I played around with various setups and I was wondering whether there's any consensus among veteran AT runners like @Albatross on a couple of points.

Weapon & damage:
First of all, to my knowledge 105 FCR has never been confirmed to outperform 63 FCR setups, right? If 63 FCR is the way to go in terms of MF efficiency, is Death's Fathom really best in slot for her? I have some doubts to be honest. I could get a better combination of damage and MF with a 6x Ist sword, coupled with Chilling GCs in inventory (rather than all out MF small charms).

For example my current setup is at 670 MF, with damage only some ~200 below my +25 CSD Death's Fathom, using this gear:

Shako 'Ist'
Crystal Sword 'IstIstIstIstIstIst'
33 Spirit
Tal's armor 'Ist'
Tal's ammy
Tal's belt
40 MF Chancies
48 MF WT
40 MF magic ring
10 FCR, 19 MF rare ring

Inventory: MF SCs, 5x Chilling GCs, Gheed's, cube

I also ran with only 3 skillers and 712 MF, which didn't seem any slower, so I was wondering... is there some Blizzard damage sweet spot/range? To me it feels that (similar to Trav) there's some range which is good enough, and after which it's better to go for higher MF. For example I didn't notice a difference in run times between 4.5k and 5k max Blizzard dmg. However, I'm still getting the hang of it, and runs aren't super efficient yet (~35 seconds on a ~5.5 boss pack map), so I don't think I've run enough for any conclusions. The 6x Ist sword provides for all the flexibility to balance MF and damage though...

Merc weapon:
I remember there was some discusion on Infinity vs Insight a while back, can't seem to find it right now. At the moment, Infinity seems much stronger to me. There are quite a few breakable CI rolls with those mummies. It is quite annyoing with Insight to either skip them or lose valuable time having the Merc kill them. Also playing rather aggressively I tend to pot 1-2 times per run anyway, picking up Rejuvs with Telekinesis while on Blizzard cooldown. It certainly didn't feel like a night and day difference in terms of mana upkeep and neither time lost due to picking up potions...

Any experience/opinions on these points?

Albatross said:
It's great having more people run and theory craft AT because I doubt the runs are as optimised as for Pit Zerkers. I'll try not to raise more questions while attempting to answer these :)

As you get closer to "maxing" your gear, 105 FCR should by all means come out on top because of MF diminishing returns. If you cast at least 50 spells during a run doing so with 105 FCR will take 2 seconds less than with 63. Of course, in practice you won't see a 2s improvement just by using a lower breakpoint because of Blizzard's cast delay and the fact we are only human.

Let's examine a well geared 3-part Tal's 105 FCR sorc sporting 669 MF. With an average of 6 unique kills and 34s runs she will score 2.017. Assuming the drop to 63 would slow her down by a single second she would need 775 MF to match the efficiency of the previous setup.

There are also 105 FCR setups which can break the 700 MF mark, but require some extraordinary items:
Shako75Godlike diadem85Godlike diadem85
Skulder's1483 part Tal's192Skulder's148
War Traveler50War Traveler50War Traveler50
Fathom30Fathom30Fathom30
Gheeds40Gheeds40Gheeds40
33 MF SCs23133 MF SCs23133 MF SCs231
FRoF401.07 ring craft401.07 ring craft40
Rare FCR ring251.07 ring craft401.07 ring craft40
Chance Guard's40Chance Guard's40Chance Guard's40
Caster amulet35Caster amulet35
Goldwrap30
714748769

In the end it just doesn't seem worth it to run with 63 FCR, granted the person doing the running can take advantage of 8 frame casting.

It's easier to find the overall damage sweet spot with Ice Blast being able to 2-shot unique horror mages. As far as Blizzard goes you are set if 2-3 shards can kill any non-immune (or broken) boss. I don't think it's possible to reliably 1-shot them without sacrificing a significant amount of MF and it's probably not worth going for in the first place.

I had a short exchange with @NanoMist about Infinity, you might be remembering that. Never managed the runes for one so I couldn't try it out, but I'm curious how it would perform. The biggest issue for me (also aggressive play style) is actually mana burn, but with Insight and 1pt Warmth I could reliably get by without using a rejuv. Disposing of immunes with either requires the merc to be close, Infinity breaks most of them, but Insight's damage output is higher because of CS. Without proper testing, I'd say it's a tie between the two.

ffs said:
I briefly compared some max Blizzard damage numbers to see how they affect run times on my map (5.33 boss avg). A couple of initial results:

~4.6k Blizzard – 34.4 second runs
~5.2k Blizzard – 29.2 second runs
~6.5k Blizzard – 30.1 second runs

Admittedly I only took small samples of 10-20 runs each so far... And of course 6.5k can't be slower than 5.2k in the long run. But still interesting that the jump from 4.6k to 5.2 immediately made a big difference, whereas the (much bigger) jump from 5.2 to 6.5 didn't seem to do much at all. Due to the small samples sizes, density in individual runs certainly plays a big role of course. Anway, the above indicates 5-5.5k max Blizzard dmg is a good amount to aim for.

I think by now I'm firmly sold on the 105 FCR setup with 6-Ist sword, adding skillers as necessary for the Blizzard sweet spot. I've also settled for Insight again. :D After moving some better MF gear to her, she now has proper resists and good life pool, and I found myself only picking potions for mana when using Infinity. Since she rarely has to pot anymore with Insight, the time added to runs from picking up potions with Infinity added up a bit too much for my liking...

Albatross said:
You still have to play around Blizzard's cast delay so it might not be worth the heavy investment.

Here's one type of "ideal" map layout, unfortunately this one is far from the waypoint and never spawns 9 packs so I have to keep looking.
decent AT map layout.jpg

5 segments will upgrade monsters when you enter the dungeon and the first teleport will trigger 2 more, including the chest room. This makes it very unlikely for the "outer" segments to upgrade to uniques/champs which means they can be completely ignored. Also, the last room on route is optional and usually skipped.

ffs said:
Great stuff @art_vandelay. I played around with it and the results of your spread sheet seem to support the conclusions above. I incrementally had a look at Blizzard ranges from 4.5 to 7.2k to see how the worst case and best case numbers changed overall. There is indeed something like a “dead zone” where improving from around 5.2 to around 6.2k damage barely changes those numbers.

Based on these numbers, seems it's a good idea to aim for either ~5.2k max Blizzard or ~6.3k+. The latter didn’t change much in my case and apparently neither for @Albatross. Sure stuff like min-maxing Ice Blast and accounting for boss modifiers changes things, but for now that’s good enough for me and I'll keep it at around 5.2k.

The “one shot” metric is of course less useful for scenarios where she fights multiple packs simultaneously, which is what she wants to do due to the Blizzard cast delay. I feel she works best on maps where at least two locations that tend to spawn multiple packs are within 1-2 teleports from each other. Due to Blizzard cooldown, that’s her fastest way to kill ~4-5 packs in a short amount of time, by going back and forth between casting Blizzards. For those scenarios the 1-shot value is not that important as monsters are hit by multiple shots. (Of course in reality they happily walk through blind spots and make you sad. :p)

Gripphon said:
[highlight]Monster Stats and Modifications[/highlight]

Boss monsters from AT taken from Basin wiki:

Plague Bearer 12982-18546 HP 0 CR
Invader 16690-22254 HP 0 CR
Embalmed 12364-17308 HP 33 CR
Horror Mage 6800-9890 HP 0 CR

Modifications that rise cold resist:
Cold Enchanted: 75%
Magic Resistant: 40%
Spectral Hit: 20% (Spectral hit adds 20% resistance to all those elements, but only if those resistances are less than 75%) - from Diablo Wiki and checks with Basin Wiki

For modifications: there are total of 13 modifications and boss monsters get 3 random on Hell difficulty. All modifiers are equally likely to spawn.

With standard equipment sorceress has -160% cold mastery and then damage depends on Fathom CD%. This means we can ignore Magic Resistant, Spectral hit and even combination of both on all monsters except for Embalmed. We can also ignore Spectral hit for all monsters who spawn with Cold Enchanted mode BEFORE Spectral hit (in which case their cold resistance becomes 75% or greater and Spectral does not increase cold resist more due to stated condition above).

[highlight]Ideal damage logic[/highlight]

I will assume player doesn't cast Battle Command and I will also assume we want to kill something for sure, not have odds of doing it so I'll assume lowest Blizzard damage roll and highest HP roll for monsters.

I would start by checking can we comfortably one shot monsters with Blizzard. Only one that seems doable is Horror Mage.
Assuming we have -160% cold resist to ignore both Spectral and Magic Resistant, we would need minimum Blizzard damage of 4945 and we need 18% CSD roll if we do without BC

Assuming we want to 1 shot even Cold Enchanted Horror Mage (75-160 = -85% CR) we would need 5346 Blizzard damage and that is reached with 28% CSD Fathom

Next I would check damage needed to 2 shot all other monsters or as many as possible. To 2 shot Invader we would need 5564 Blizzard damage. That number can't be reached without casting BC or additional skill somewhere.

To 2 shot Embalmed with both Spectral hit and Magic Resistant (93-160 = -67% CR) we would need 5183 Blizzard damage and 23% CSD Fathom

Next I would check Ice Blast damage.
If we want to 2 shot Horror Mage, we would need 2472 damage. That is reached if we reach 1 shot with Blizzard anyway. If we want to 2 shot Horror Mage with Cold Enchanted, we would need 28% CSD Fathom.

We can't 2 shot any other monster with Ice Blast. 3 shot is also unreachable without gear changes. To 4 shot invader we would need 2782 Ice Blast damage and such is not reached without additional skill which would also increase Cold Mastery and change number needed.

To 4 shot Embalmed with both Spectral and Resistant Skin we would need 2592 Ice Blast which is reached with 24% CSD Fathom.

It seems to me going below 5k or above 5.6k Blizzard damage is not profitable due to either killing speed or MF loss. What real ideal number is depends on what player has.

EDIT:
Going by numbers above I would guess ideal damage for Blizzard to reach is either 5233 (24% CSD) or 5402 (28% CSD). Depends which one player is closer to. Each of these opens new killing ideal spots. We can still 2 shot Invaders unless they spawn with near max HP and Cold Enchanted monsters will also give us trouble here and there.

ffs said:
The other day I made a Sorc spreadsheet to more easily calculate fire damage against specific monster types. I realized it's easy to expand it to other targets and builds and I'm in the process of doing so. Will post it when it's done.

In the meantime I player around with it for Blizzard and Ice Blast, and ran it through the AT boss types in order to get a better idea of whether I should go with DFathom or 180 MF sword. I personally only have rather average Fathom rolls so I was interested in seeing what I should go with. DF numbers were the same that @Gripphon mentioned, so I take that as a good sign that I didn't screw up the spreadsheet. :)

The below is comparing how many maximum hits are required with Blizzard and Ice Blast, looking at setups with typical DF/Tal Rasha gear and 180 MF sword with 2/20 amulets and 5 skillers in inventory. Both setups are with Insight Merc, 105 FCR and same unique MF breakpoint. Sword setup reduces enemy CR by 180 and Fathom by 160 unless extra skills (or casting BC) are included. The sword setup does require a 2/20 amulet to be competitive with Fathom, and I was more lucky in that regard than with a high roll Fathom (my highest is +22 CSD), so this might not be useful to everyone. Still thought I'd share this here.

ffs_blizz_IB_AT_breakpoints.png
(To avoid confusion, "BC/+1" means getting +1 cold skill somehow, with BC or otherwise, "BC/+2" means getting +2 somehow)

Conclusions:
  • When not casting BC:
    180 MF sword setup hits more breakpoints. Also some of the breakpoints that DF can hit require high rolls (27, 28) and others require above average rolls (23, 24).

  • When casting BC:
    Depends on Fathom roll.
    With +30 CSD, Fathom hits all breakpoints. 180 MF sword in comparison still needs one extra skiller to hit 2 breakpoints, if doing so dropping one 1-2 uMF breakpoints. This is where Fathom is better. Fathom with <30 CSD and 180 MF sword are pretty much the same. Fathom below 25 CSD again loses a few breakpoints.
This is only looking at damage of course, ignoring other factors like life amount and resist. Life is probably a bit higher with 180 MF sword with a couple +life skillers, whereas resist is better with Tal setup unless using very good MF/res small charms with 180 MF sword.


Brief discussion of viability of short runs.
zemaj said:
Funny you should mention that... was doing some AT runs yesterday and had something like that come up. Some backstory: my AT map is a little odd in that you have to be careful to stay close to one side of the path at the start of a run or you will spawn the sparkly chest tile. Anyway, at my first boss pack spawn point (which spawn two packs >70% of the time), I got 4 champs and a bosspack... since I had kinda messed up my entrance tele-blitz anyway, I decided to bork this run entirely and went straight to the chest.... and was greeted by three boss packs and some more champs (<10% to get so many packs in the chest room)! I've been thinking if I could get such runs repeatably, only loading 3or4 tiles per run with 4 boospacks and 6+ champs, I'd definitely do that...

Albatross said:
@ffs I've tried one a long time ago, but I think the chest room was adjacent to the entrance, probably couldn't go below 2.0 adjef. Generally, the faster the run the more time is wasted on getting to the monsters, save/load overhead, etc., which makes it difficult for this type of strategy to work.

@zemaj the spawn distribution is still mostly random, likely no way of forcing it to behave that way.

ResTTe said:
Yeah, this is what i saw on a pitzerker. You really want all of the packs to spawn on your way to lvl 2 in the pits. You also want to have as many packs as possible, cause killing 11 packs in 66 seconds (6s per pack) is pretty easy, but killing 6 packs in 36s is impossible... Talking about he whole run duration ofc.

@Mir's alternative counting method.
Mir said:
When I tried to calculate the density of rooms on my map I also decided to calculate the chance of boss/champion pack to spawn or occur and I thought this information might be useful for others too when they want to decided which rooms to concentrate on. Of course there is a correlation between density and chance of occurrence but it might give another conformation or help with decisions.

What I did is quite simple:

% to occur = [number of occurrences per room over 'N' runs (no matter the number of packs)]*100 / [Total occurrences = 'N']

For example:

16 runs
Code:
Rooms     2        3    7    8    6    5    4 (Chest)

Densety     9%    34%    2%    8%    18%    12%    16%
                          
OCCU    44%    100%    13%    25%    75%    75%    100%
 
Last edited:
Will have a session of upgrade of my map soon, i forgot how detailed it was. I can even have few steps without effectively running the map, so it's about perfect for my situation (RFL round, close to the middle of the run. Boss counting will be counted in, but it's still lots of time saved in the process before!)
 
This MFO I ran half of my (few) runs with Pit Berserker and the other half with AT Blizzy.

For both characters I tweaked gear and build and recently found what I think are nice improvements for both.

As for Blizzy, I thought this would be a good place to share some of the things I tried and what I ended up preferring.

REVISED 180 MF SWORD SETUP
The majority of MFO Blizzy runs were done with this gear:
  • Shako 'Ist'
  • Enigma
  • +2 Cold, 20 FCR craft amulet
  • 180 MF Crystal Sword (6 Ist)
  • 35 FCR Spirit
  • Arachnid Mesh
  • 40 MF magic ring
  • FCR/15 MF/resist/life ring
  • WT
  • TO gloves
  • CtA/Spirit switch
  • Build: 20 each Blizzard + synergies + CM, 1 TK, Warmth, Shiver Armor, pre-reqs, FO
One of the archive posts above include my original conclusions of how the sword setup above compares to setups with Death's Fathom, finding it outperformed Fathom in the majority of boss mod cases. Full post can also be found here.

Now during MFO I switched back and forth between the sword and Fathom + Tal variants, tracking run times and comparing how clear speed and safety aspects. They were mostly indistinguishable for a long time. Despite Fathom/Tal provided 75 LR/CR, I still found myself potting quite a bit with both setups. I figured reducing that was the most obvious area that could be improved for more efficient runs, so I tried a few things to address that.

The game changer in this respect was starting to use Enigma. I had often thought about using it before, but always figured Skullder's offered better MF (and with facet even better damage and MF). But it's crazy how much of an impact LPK and the higher life has for this character. It reduces potting immensely and saves a good amount of time not picking up many potions. Add 8% damage reduction and significantly higher life, this resulted in more aggressive gameplay and faster runs, as well as starting most runs with full or nearly full health and mana. Even felt like damage to mana was useful at times.

Life with Enigma is above 2.1k (!) after BO. That is really quite a lot for an AT Sorc (at least for honest players using current patch gear ;)).

Using Enigma means losing 2 MF breakpoints in comparison to Ist'ed Skullder's, but in my case it was clearly more efficient. 2 MF breakpoints in case of my run times translate to 0.2 seconds run time... and my run times improved by more than 2 seconds. So that's that.

FATHOM + ENIGMA
I then also tried Enigma with Death's Fathom, eventually ending up with this:
  • Shako 'Ist'
  • Enigma
  • Death's Fathom 'Ist'
  • Spirit
  • 2/20 amulet
  • Arachnid Mesh
  • Chance Guards
  • WT
  • 40 MF ring
  • FCR/MF/res/life ring
With 6k min Blizzard damage and -175 ECR, this provides much higher damage than both Tal Rasha and 180 MF sword setup (~20% increase in my case). It checks every single box regarding damage breakpoints vs. the various bosses/modifiers. Also Fathom roll doesn't matter much either, I use one with only 21% CSD and it hits all target breakpoint depicted in the post linked above without casting BC.

The downside is losing ~30-40 MF depending on which other setup you compare it to. The efficiency of 30 MF in my case is made up for when run times improve by ~0.5 seconds. As mentioned above, my run times improved by more than 2 seconds in comparison to Tal Rasha, so in that way it seemed strictly superior to me.

I'm still torn between this and the 180 MF sword variant, though. On first sight the Fathom + Enigma variant seems stronger, given more damage and resist at the expense of only a couple of MF breakpoints. However it's important to realize that going up to 6k damage doesn't help that much in comparison to 5.2-5.5k range. You can check the above linked theorycrafting for why Blizzard damage of more than ~5.5k only rarely reduces the number of hits required to kill a boss. There will be situations where it does help, though, and extra LR from DFathom helps as well. So I'd say it's a great option with minimal MF loss, that is likely at least on par with the 180 MF sword variant.

JEWELRY
Having lucked with a 2/20 amulet I still used it with the DFathom + Enigma setup, but is not required at all. One could simply use 20 FCR gloves instead of Chancies and some random amulet with Sorc skills and MF. This would also increase cold resist further when using TO gloves, plus potentially good resists/life/other stats from amulet. (For example I have an ammy with +2 Sorc, 17@, 25 MF with some life, which I considered using along with TO gloves instead of the 2/20. I just felt I didn't need more life/resist and thus wanted to include some more MF via Chancies.)

Other craft amulets provide further options of course. 2 skills aren't really required on amulet either here. As mentioned 6k damage doesn't do much for the amount of hits required to kill a boss in comparison to ~5.5k, so dropping a skill level here or there is completely fine. Meaning numerous craft amulets become really nice options.

As to rings: For a while I also used Wisp Projector, in particular with the 180 MF sword. It pretty much eliminates lightning damage being an issue, and I can highly recommend it if people lack a good amount of MF/LR charms. In comparison to the default Nagelring it's 10 MF loss, which is really close to nothing as it generally translates to one MF breakpoint at most. I dropped it again for a 40 MF ring, but just because I realized with >2k life and LPK from Enigma I no longer needed to pay that much attention to lightning damage tbh.

MERC
There was some discussion with Albatross in the MFO thread on Merc gear as well. I checked a few numbers and used Owlie's Merc dmg calc to finally settle for this gear:
  • GPA Insight
  • GFace 'Cham'
  • Fortitude
Of all armor choices, Fortitude offers the most damage by a healthy margin. Its downside is slightly slower Might triggering in comparison to an IAS armor, but it's not a big difference (see this post, which also includes the Merc dmg calculator). Might triggering in general is less reliable for those short AT runs. Fortitude is guaranteed 300 ED on the other hand -- way to go in my book.

CNBF I considered key by now, but wasn't sure whether to go for Cham'ed Andy's or Cham'ed GFace. GFace starts to be better than Andy's when facing monsters with >9k HP. This means that GFace performs better against all bosses and most champions, with minimally slower Might triggering that I figured wasn't worth focusing on. Given CI uniques are his main task, I don't see any reason not to use GFace.

The only practical question mark was leech, but I quickly realized Merc doesn't need it at all. He was never even close to dying during my MFO runs.

GPA Insight provides the highest DPS when using Fortitude and Cham'ed headpiece, so that just followed the above considerations.

TLDR
I don't know how many people seriously ran AT Sorc with Enigma -- but wanted to share the above here because I think Enigma is incredibly strong for this character, regardless of which weapon is used. I'd be curious as to experiences of others.
 
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