How good is the d20 engine for computer games?

[Quertus]

Hmmm… it feels like there’s multiple dimensions to this question.

“Is a d20 base good for modeling physics in a computer game?”

Sure. Almost nobody will care about the difference between 87% and 85%, and exceedingly few people have the math intuition to really have a feel for those numbers to begin with. The edge cases of “always a 5% chance to miss” / “sufficient skill difference means always / never sneak past”… seems ok to me, but might bother some. Shrug. More on having to deal with both paradigms in the same game later (senility willing).

Are races, classes, levels etc good in a computer game?

Absolutely.

Are standard / move / immediate actions good in a computer game?

Eh, maybe? There’s two basic cases I can envision: turn-based and real-time.

Turn-based

In a turn-based game, it’s really easy to differentiate move / full round / etc actions, to set flags like “charging” or “raging”, or to set variables like Power Attack or Expertise. Out-of-turn actions, otoh, are a pain. If you’ve played MtG computer games, and can imagine scaling them up to a 10-player free-for-all, and having to wait for 10 players to decide (1-at-a-time, mind) whether they want to respond to each action - or even just having to poke those prompts yourself for every action the 9 AIs take - I think you can see how bad this could get.

Real-time

In a real-time game, immediate actions are just button presses that don’t interrupt whatever action you were taking - you can be in mid sword-swing and give yourself Sudden Haste or engage Deep Impact. Otoh, the system differentiating between moving up and attacking, charging, spring-attacking, or even full attacking seems a bit problematic. Also, “initiative” can be a weird concept. And some things (like limited-use rerolls) are really rough.

Is 3e D&D suited to being played on a computer?

No. 3e is a roleplaying game. Computers can’t do roleplaying games.

Is the 3e combat engine suited to computer play?

Hmmm… I’m going with “yes”. In fact, I’ll go out on a limb, and suggest it’s more suited to digital than pen and player. No, I haven’t forgotten my meds, I’ve actually got reason(s) for saying this.

Rocket Tag

One of the big complaints about 3e is that (at higher optimization, at least) it lives pretty close to the “rocket tag” end of the “padded sumo / rocket tag” spectrum. But you know what else has rocket tag? Games with actual rockets! I’ve enjoyed plenty of games with rockets; simply reskin those as an übercharger or Finger of Death Spell, and what’s the difference?

Information wars

If you don’t perceive a hidden target / trap / whatever, the computer can simply not render it for you. Done. No “out of character” information concerns.

Is the concept of being a fantasy adventurer suited…

Oh heavens, hells, and planes of indifference in between yes!

Is 3e suited to delivering the full adventurer experience… on a computer?

Eh… maybe? It’s… kinda passable in pen and paper.

I still remember the time my brother came to me because his character (a totally OP assassin) in Elder Scrolls: Arena kept dying before he could reach the next town. I investigated, and saw his status was “consumption”, which I fortunately recognized as a name for a deadly disease.

I don’t know if a 3e engine would produce such memorable moments. It has poison, and disease, and traps, and carrying capacity, and travel time, and exhaustion (I guess), and fast travel magic (eventually… if you’re one of, like, 2 classes or something), and lots and lots of material, and a quick leveling system suited to modern gamers, and the ability to set your “handicap” / difficulty level with a vast array of completely unbalanced choices (including variable movement speed, jump distances, and “terrain options” (flight, climb/swim skill/speed, etc)), but… where’s the jumping on alligator heads of Pitfall? Where’s the “creating your own spells” of Elder Scrolls: Arena? Where’s the unique memorable moments where you’re enjoying Exploring the strange, new world as much as your character? Where’s the joy?

In pen and paper, you can show me a place where the rocks float, and I can respond, “oh cool! I know, let’s…”. But… unless you just embraced the imbalance, and let people mod their own classes or something, I’m not sure where the “cool”, memorable parts of using a d20 engine would be.

Pool of Radiance (buyer beware, modding necessary),

Why does PoR require modding?

You kidding? There are hundreds of other computer roleplaying games that can be used as point of comparison. For a non-d20 example that can be analyzed for how much a system does or doesn't make a difference, there's the Exile / Avernum series by Spiderweb Software. Exiles 1 to 3 are the originals, using one system, old Avernums 1 to 3 are isometric remakes using a second system, Avernums 4 to 6 continue the series with a third, and finally, the new Avernums are remakes of Avernums 1 and 2 using a new engine and a fourth system.

So, using Exile: Escape from the Pit, Avernum and Avernum: Escape from the Pit, you have the same campaign implemented with three different engines and three different sets of game rules.

Similarly, Icewind Dale uses an older, 2nd Edition AD&D based system (the same as Baldur's Gate, if I recall right), while Icewind Dale 2 uses d20 3rd edition. It's about as straightforward as can be to review where the new system improves gameplay and where it does not.

Apologies if I missed it, but do you (or does anyone) have comments wrt how changing the underlying system affected any of those games?

[GloatingSwine]

That's no different from a d20 game. There's no assumption you will know the TN in advance of making the roll.

A rough estimate of difficultly (or even exact DC) is reasonable for a DM to provide in any case where the character has time to assess in advance. But it's not assumed.

In cases of AC and saves, it's very likely you won't know before choosing which form of attack / spell to use what your odds of success are.

There are differences in videogames, which will often be balanced more around combat than non-videogame implementations of the rules and because they don't have a DM who can dynamically adapt the campaign combat game overs are the dominant stakes, which means more saving and reloading and trial and error until you pass the combat.

Which means that open information is a path to the same place the player is going to reach (finding out which things work on given enemies) without the frustration of repeating it.

That's also why they've tended to away from RNG and towards thresholds for out-of-combat mechanics, because they will get savescummed even more.

Why does PoR require modding?

It's old and busted. It was busted when it came out (it had a suicide pact with Windows and if you uninstalled it it bricked your PC and you had to reinstall your OS), and time has not been kind to many games of that era in terms of making them run on a modern OS.

[warty goblin]

Hmmm… it feels like there’s multiple dimensions to this question.

“Is a d20 base good for modeling physics in a computer game?”

Sure. Almost nobody will care about the difference between 87% and 85%, and exceedingly few people have the math intuition to really have a feel for those numbers to begin with. The edge cases of “always a 5% chance to miss” / “sufficient skill difference means always / never sneak past”… seems ok to me, but might bother some. Shrug. More on having to deal with both paradigms in the same game later (senility willing).

This isn't really a question of modelling physics, arguably the point of a probabilistic model is so you don't have to do the physics. For an easy example, compare XCOM and Phoenix Point. XCOM uses a probabilistic hit calculation, it's all +10% and -25% and so on and then you just roll a dice. This leads to weird outcomes, like the infamous missing a dude from six feet with a shotgun. These suck and nobody likes them.

Phoenix Point by contrast uses a system where you choose a target, and then the game generates random trajectories from the muzzle of your gun and does the actual physical collision detection. There actual trajectory of each bullet is still random, but it pretty much solves the point blank miss problem because, well, you can't do that. At point blank range the trajectories all pretty much impact the target and you will hit. And if you can, it's because there's something like a pillar in the way, which you see when you aim.

The thing is you could pretty much play XCOM on a tabletop because it reduces everything to a dice roll. You really can't do that with Phoenix Point. In a lot of ways I think running TTRGPs straight on a computer is sort of missing the strength of the computer, which is that it can do more interesting and complex stuff in terms of world simulation than a tabletop game can.

[NichG]

Ooh, another thing that can work well on a computer but is death to tabletop - having literal legions of summons. You can absolutely make a computer game where you're a necromancer commanding a thousand units of undead on a crowded field and it's basically no harder to do than a squad of six characters, at least if you're doing it realtime or 'necromancer takes turns, troops act in parallel' sorts of setups. That sort of thing doesn't work on tabletop very well, and tabletop rules tend to evolve to avoid it becoming a situation, making armies of undead more of a plot power than an actual character power you can practically get in normal play.

[Vahnavoi]

Apologies if I missed it, but do you (or does anyone) have comments wrt how changing the underlying system affected any of those games?

I can provide commentary, but I'll note any commentary will make more sense if you've actually played the games. It will take a while to compile a list.

[TaiLiu]

Ehhh, a lot of the things they added that go against tabletop (like Grazing Hits) actually make it a worse game overall. They're just there to paper over the horrendous powercreep the game has experienced.

Do you mind explaining this? I believe you about the power creep. But I'm not sure how something like grazing hits hides power creep.

[Rynjin]

Do you mind explaining this? I believe you about the power creep. But I'm not sure how something like grazing hits hides power creep.

IIRC Grazing hits were basically put in for the express purpose of making sure enemies could always hit and deal a little bit of chip damage to players with high AC bonuses, because AC had gotten so high that enemy attack rolls couldn't keep up. This, in turn, meant healing spells (really, any healing effect) were basically powercrept.

On the flipside, it ensured players with less optimized character builds could always hit enemies and deal chip damage, because enemies had gone through the same kind of numbers inflation.

This especially helps Rogues, who get to add Sneak Attack on grazing hits, and makes up a smidge for their 3/4 BaB.

[TaiLiu]

IIRC Grazing hits were basically put in for the express purpose of making sure enemies could always hit and deal a little bit of chip damage to players with high AC bonuses, because AC had gotten so high that enemy attack rolls couldn't keep up. This, in turn, meant healing spells (really, any healing effect) were basically powercrept.

On the flipside, it ensured players with less optimized character builds could always hit enemies and deal chip damage, because enemies had gone through the same kind of numbers inflation.

This especially helps Rogues, who get to add Sneak Attack on grazing hits, and makes up a smidge for their 3/4 BaB.

Oh, I see. I wasn't aware of the history.

[Quertus]

lIt's old and busted. It was busted when it came out (it had a suicide pact with Windows and if you uninstalled it it bricked your PC and you had to reinstall your OS), and time has not been kind to many games of that era in terms of making them run on a modern OS.

Ah. I played it on the C64, so I wouldn’t know about such things. I would, however... “Insert disk 8, and press any key to continue.” … … … know about extensive load times.

I can provide commentary, but I'll note any commentary will make more sense if you've actually played the games. It will take a while to compile a list.

I haven’t played them. So a single example, like “Minecraft has (meaningless fluff) accomplishments called achievements iirc, which can only be acquired while playing the game. It used to be, you could acquire achievements while playing in a game even if you had previously edited said game (in editor / god mode called ‘creative’); now, games which have been played in creative are ineligible for the collection of achievements.”, would probably help me more than a full list of all the changes, especially if said list required knowledge of the game in order to parse it.

[Gnoman]

As a very straightforward example, anyone familiar with GURPS knows that the combat is absolute garbage because of all the calculations involved in getting a realistic (or realistic enough) result. Pick a gun and a target. Pick a body part on that target. Look up the range modifiers on the specific weapon you're using, and the specific kind of damage it's dealing. Look up how the ammo you're using affects the attack roll. Look up the size modifiers and damage reduction/resistance/mitigation modifiers of the body part you're aiming at. Check the tables for how cover and concealment affect the attack. Check the tables for how wind conditions and high/low ground affect the attack. Check the table for how lighting affects your attack. Check the table for how the position of the moon affects your attack. Check the table to see how both your and your target's birthdays affect your attack. Resolve your attack. Roll on several more tables to figure out exactly how debilitating that wound is going to be for your target. Roll on several more tables to figure out exactly how debilitating that recoil is going to be for you. I'm being a bit hyperbolic, but the point is that it's very tedious for what is, in-universe, a simple "point and shoot" mechanic, just because GURPS is trying to be so realistic that you have the option to factor in a thousand different modifiers for each attack. It's an agonizing process.

This isn't even remotely true.

[GloatingSwine]

Ah. I played it on the C64, so I wouldn’t know about such things. I would, however... “Insert disk 8, and press any key to continue.” … … … know about extensive load times.

You’re probably thinking about a different Pools of Radiance. The one on PC from 2001 was the first CRPG to use 3rd edition rules.

It was not well received even aside from it being top tier malware that could nuke your entire operating system.

[Tanarii]

This isn't even remotely true.

Funny, when I read it I was thinking "this is a perfect description of trying to run GURPs"

[Vahnavoi]

@Quertus:

Here's a few major points. First, Exile to Avernum continuum:

Character creation and advancement:

- Both Exile and Avernum use a classless skill-point based system
- In Exile, all skills are available at the start and are bought at flat cost of skill-points and gold throughout
- In old Avernum, skills have ascending costs and some special skills are only available through trainers, items, traits etc.
- In new Avernum, skills are arranged in a tree-like structure. Skills lower in the tree are bought first and both unlock and set the maximum for higher skills.
- In Exile, basic attributes (Strength, Dexterity and Intelligence) are bought with the same point budget as other skills. Strength and Intelligence influence hitpoints and spellpoints at character creation and, in case of Strength, influence hitpoint growth on level-up. Beyond this, hitpoints and spellpoints are skills like any other and can be bought directly with points.
- Old Avernum adds Endurance to basic attributes and makes a sharper distinction between primary and secondary attributes. Hitpoints and spellpoints are now secondary attributes, raised by spending points on Endurance and Intelligence, respectively.
- New Avernum tracks attributes separately from skills.
- Exile 2 and 3 add a short list of advantages and disadvantages that can be picked from at character creation. No limit is placed on how many advantages or disadvantages a character can have, but they do influence how much experience is required to advance in level. (Advantages increase XP requirements, disadvantages lower them.)
- Old Avernum expands the lists and places a limit on number of advantages and disadvantages. (I forget if it's two in total or two of each.)
- New Avernum has a more expansive list of traits that are selected from throughout the game, much like feats in d20 system
- Exile and old Avernum (maybe, not sure I recall right) require visiting trainers to use skill-points, and the trainers are placed with this in mind. New Avernum allows using skill-points whenever and trainers are repurposed as advancing some skills for money

What difference does this make:

- In Exile and old Avernum, characters don't suddenly improve midway through exploration. After gaining a few levels, it's worth it to return to civilization.
- In Exile, finding a trainer in town is a pleasant surprise and if you have the money and skill-points, you're almost always happy to improve your character. One level is typically worth 5 points, which is enough for all but the most expensive two skills (Mage and Priest spells), so before very high level levels (where skill-points per level is reduced to 4 and then 3) a single level will always get you at least something useful.
- Also in Exile, the first few points in most skills make the biggest difference, so there isn't much pressure to min-max. What the skills do is documented and the game tells you some of the important early breakpoints, but beyond this the exact value of raising skills is somewhat obscure. Behind the scenes, the game uses a combination of die rolls and look-up tables, with somewhat counter-intuitive intervals. However, the number of skills is small enough that a player pretty much always knows what to increase, even if it's not clear how much of a difference it makes.
- In old Avernum, ascending skillpoint costs means that after a point, a single level-up no longer is enough to increase primary skills. What skills do is much better documented, but sometimes the tooltips are just wrong (for whatever reason). The game shows to-hit percentages in message logs, so effects of skill-increases are more easily seen, as are the caps (to-hit ranges from 5% to 95%, suggesting the game might actually roll d20 behind the scenes.) Because some trainers allow increasing skills with just money, this changes approach to training: rather than use them at first opportunity, it's better to save them for later.
- In new Avernum, because the order at which points are spend matters, min-maxing is strongly incentivized and trainers are almost always spared for last, because they may allow breaking a point-cap. Additionally, since trainers tend to be very expensive, the approach to money changes, from using it when you have it, to hoarding it for later to squeeze every last drop out of it.
- Exile uses die rolls or other probabilistic methods to check things such as disarming traps, unlocking doors etc. This means even a low skill can carry a character through, provided they are willing to try and retry the same thing. Old and new Avernum move towards treshold approach: you need a skill at certain level to do things, the game tells you this, and so you know when to stop trying.
- This also means that in new Avernum, there's more strategizing about how many points exactly to spend on treshold skills that open new paths and such, since not spending enough means less options and spending too much is a waste.

Item management:

- Exile does not have permanent item memory save for specifically designated safehouses. This means that if you leave an item lying around and leave an area, next time you return, it will be gone. Shops are placed with this in mind. This is important.
- In old and new Avernums, all indoor locations have permanent item memory. Outdoor encounters do not.
- In Exile, food is an abstract accumulated resource similar to gold. Food is spent on long rests and steady time intervals, and not having enough food leads to starvation damage. Food vendors are placed with this in mind. This is important.
- In old Avernum, food items take up inventory slots. There's a large variety but the differences are mostly cosmetic. Food is only used on long rests. Lack of food only means inability to long rest outdoors.
- In new Avernum, food items are consumables, like potions or scrolls. There's a large variety with some numerical differences.
- In Exile and old Avernum, characters who fall in combat drop all their belongings.
- In new Avernum, characters who fall in combat retain all they are carrying.
- In Exile, amount of items carried is primarily limited by the small number of item slots. Equipped items and other stuff exist on the same list. Exile 2 or 3 adds a weight limitation based on Strength.
- In old Avernum, amount of items is capped by slots and total weight. However, equipped items are placed on a character's paper doll and do not take backpack space.
- In new Avernum, only items on a character's paper doll have their weight counted. Backpack has more space. Additionally, there is a free-use, unlimited junk bag for everything player finds no use for but might want to sell for money.
- In Exile, enemies rarely drop equipment, and what they drop is pretty random. Most loot is in the form of money and food.
- In old Avernum and I think new Avernum, monsters have inventories, meaning they drop semi-logical quantity and quality of stuff. A lot of wealth is tied to "vendor trash".
- There's a much larger variety of equipment in Avernums, with wider variety of item effects
- Exile and old Avernum track ammunition of all kinds. New Avernum only tracks thrown weapons, bows get unlimited arrows.

Encounters and resting:

- Exile has wandering monsters both indoors and outdoors. Indoor locations keep regenerating monsters at set intervals until enough have been killed for a map to be considered "emptied".
- Old and new Avernums significantly reduce indoor wandering monsters (might do away with them completely, not sure)
- I'm not sure what the difference in quality and quantity of outdoor encounters is. In Exile, they are technically unlimited, but past a point start fleeing from the player characters more often than not. Avernums tend to prompt the player on whether they want to fight lower level encounters.
- In Exile, hitpoints and spellpoints both slowly regenerate as time passes.
- In old Avernum, only hitpoints regenerate. Spellpoints have to be specifically rested for.
- In new Avernum, First Aid skill regenerates some lost hitpoints and spellpoints after combat. Otherwise, regeneration requires use of spells and consumables.
- Exile has long wait function for recovering hitpoints and spellpoints indoors. Old Avernum might not have, I'm not sure. New Avernum, if it exists, I didn't use it once, since it would serve no purpose.

What difference does this make:

- In Exile, unless you save-scum like a little kid, it's possible to lose items. A character dies and their friends can't carry all their equipment? That equipment is gone and has to be replaced.
- In old Avernum, the above can still happen, but mostly just outdoors. Indoors, there's no harm to leaving a dead character's stuff where it is and coming back to fetch it later.
- In new Avernum, there is, as far as I recall, no way to lose non-consumable items, save for selling them to a shop.
- This matters hugely because all the shops were placed and stocked with the Exile paradigm in mind. In Exile, it's a good thing every corner of the map has its own weapon and armor shops, because you might actually need to buy something from them. In old and new Avernums, there's a point beyond which those shops serve no point. You are literally swimming in equipment looted from enemies, much of what is equal or better to anything in shops. In Avernums, majority of all items are reduced to vendor trash that you only pick up to sell for cash to use for trainers and such.
- Food vendors are hit particularly hard by this. In Exile, they are vital, in old Avernum, they're nice but not necessary, in new Avernum, they're mostly just there.
- In Exile, you occasionally have to make decisions of what to spare and what to abandon. Using weaker consumables in combat is a sane move simply to make room for better loot. You don't have much room for alternate loadouts, so each character tends to carry only what is essential to their purpose. Anything not immediately usable but too precious to abandon or sell is best left in a safehouse.
- In old Avernum, there's a lot less decisions to make. Lighter and more valuable items are preferable if you don't want to backtrack, but since items are permanent, it's possible to just come back and loot everything not nailed down and on fire.
- In new Avernum, it's possible to take absolutely everything in one go. This may appeal to your packrat instincts but genuinely removes all strategic depth from item management.
- In Exile and old Avernum, there are all kinds of strategic reasons to stop midway through exploring a location and returning to town: going to restock on food or items, going to train, going to rest, going to a healer to return dead characters to life. In new Avernum, only the last really applies, meaning indoor locations are much more one-and-done.
- In Exile, it's possible to find a dark hole to hide in and long wait to recover, at the expense of having to fight past accumulated wandering monsters. In Avernums, this is no longer an option.
- In Exile, while a skilled player probably won't see starvation past initial stages of the game, the food clock is always there, and there is incentive to try even the mystery meat of an ogre kitchen. It also puts a natural limit to how long you can spend in the backwater boondocks in the middle of nowhere. In old Avernum, odd food items mostly just take space, you can just stock up on bread and dried meat and be done with it. In new Avernum, role of food is eclipsed by other consumables as the game advances.

---

So, that's something for a start.

I can do a similar thing for Icewind Dales, but it will have to wait.

[Quertus]

@Quertus:

Here's a few major points. First, Exile to Avernum continuum:

Wow. I don’t understand all of it yet (reading comprehension being what it is), but wow, that’s way more detailed than I expected, and way more vectors of difference than I expected changing the underlying engine to make, too.

Of course, some of those changes are… odd… like still using the d20 engine, but allowing people to just buy feats, skill points, or extra spell slots or something. Um… except Otyugh holes and Pearls of Power exist, so… that kinda already exists in d20, just with an added layer of abstraction.

So it’s tricky to ask “what’s in a system” when “d20” could encompass many of these variables as simply variant d20 systems. You’ve given me a lot to think about.

[Vahnavoi]

The above only scratches the surface. If that's already more differences than you expected an engine and system change to make, I have no clue what you expected.

To compare to tabletop side for a moment, even if I limit myself to just d20 SRD material, the (meant to be mutually exclusive) Unearthed Arcana variants would allow me to construct games that play entirely differently. On the character creation side, using the generic classes variant instead of the core classes is at least as massive a change as all the changes between Exile and Avernum character creation.

Anyways, moving on to Icewind Dales for a moment:

Character creation and advancement:

- Icewind Dale is based on 2nd AD&D, with all its quirks. Humans can't multiclass, but can dual class instead. Non-humans have limited class selections, with some having more class and multiclass choices than others.
- Different classes have different experience point requirements for leveling up
- For Icewind Dale multiclasses, gained XP is divided evenly between all classes a multiclass character has. A multiclass character hence has levels in several classes and abilities from all of them, but each individual class at a lower level than single class characters.
- For dual classes, a human character entirely stops progressing in one class and starts over in another, retaining old features up to the point where they switched. A common dual class would be, say, taking two levels of Fighter for the hitpoints, before continuing in another class.
- No standardized skillpoint system. Thieves have their own small skill list they get points for, Fighter types get proficiencies.
- Icewind Dale 2 is 3rd Edition D&D based. All races can be of any class, multiclassing is only restricted by some class compatibility considerations.
- Class levels are bought one at a time. When multiclassing, progression in new class starts from the beginning of their chart.
- Experience points to advance levels are the same for all classes, but multiclass characters take penalties for uneven advancement or taking too many non-favored classes
- Skillpoint system and skill lists are standardized, but cost of skills varies by class.

What difference does this make:

- Number of possible character combinations is massively greater in Icewind Dale 2 than in Icewind Dale.
- On the flipside, proportion of good character combinations, especially when it comes to multiclassing, is significantly reduced. True to 3rd edition form, it's possible to take non-synergistic class combinations and screw yourself from gaining late level benefits. Spellcasting multiclasses are hit especially hard: in Icewind Dale, a, say, fighter/wizard/thief might be few wizard levels behind a single class wizard, but their other levels are close to or higher than their wizard level, the gained benefits offsetting the losses. A 2nd Edition Fighter 10/Wizard 9/Thief 11 is in a very different spot than 3rd Edition Fighter 5/Wizard 5.
- Fighter types and rogues actually get relatively better, they lose less and gain more from multiclassing, and in general have more different things to try both in and out of combat.
- Icewind Dale 2 has massively more micromanagment in character progression and abilities, and consequently much greater capacity and incentive for min-maxing. The situation is not quite as bad as on the tabletop, due to shorter list of feats and skills, but very much noticeable.
- At the same time, since both games use the same isometric point-and-click stop-and-go engine, all the extra character abilities don't change moment-to-moment gameplay much. Especially on the spellcaster side, strategies remain much the same.

Inventory management:

- Icewind Dale has Strength-based weight restrictions, but in practice these come up less than the very limited amount of inventory slots.
- Icewind Dale 2 has Strength and encumberance based limitations, but a much larger amount of slots and specialized containers for holding some items, such as scrolls or consumable potions.
- usable equipment is sharply limited by class and proficiency in Icewind Dale
- usable equipment has less class-based restrictions in Icewind Dale 2 but non-proficient users suffer penalties.

What difference does this make:

- Inventory management is much less of a hassle in Icewind Dale 2 and character ability feels like it matters more.
- On the flipside, increased inventory capacity in 2 allows for more hoarding. The game is self-aware of the fact and will mock you for carrying certain useless items around.

Character interaction and dialogue:

- In Icewind Dale, some dialogue options change based on Charisma and sometimes class. However, there is not much of it.
- In Icewind Dale 2, dialogue options change based on Charisma and class as well as ranks in particular skills (Bluff, Intimidate, Diplomacy). Which character is used for interaction matters, these are not universally applied to the whole party.

What difference does this make:

- Neither game is a stellar show of how to use multiple choice dialogue, but Icewind Dale 2 puts a lot more effort to it. It really does make a difference to have your Monk or Paladin be the one doing that talking over the Barbarian, and skill ranks occasionally open interesting alternate interactions.

Spellcasting:

- Icewind Dale has Clerics, Druids, Rangers and Paladins using divine casting rules, meaning they can cast in armor and choose to memorize spells from their entire class list. Wizards use arcane casting rules, meaning they can't cast in heavy armor and have to add spells to their spellbook from scrolls.
- Icewind Dale 2 adds Sorcerers and Bards to the list, using spontaneous arcane casting rules and picking spells known at level up.

What difference does this make:

- I'm focusing on the new addition of spontaneous casters, because there the change is most tangible. On one hand, being able to pick spells on level up is more customizable and less reliant on loot than transcribing spells. On the other, having this specific use for scrolls is what set Wizards apart from Clerics and Druids in the first game, and the fact that Sorcerers can't interact with the world in this way will make you a sad puppy if you didn't pick any Wizards for your party in the second.

---

It's been longer since I played Icewind Dales than since I played Exiles and Avernums, so this is best I can do for now.

[Quertus]

The above only scratches the surface. If that's already more differences than you expected an engine and system change to make, I have no clue what you expected.

Ah, not “more differences”, but… more categories under which to place differences? Like the concept of how the underlying system changes the value of converting various resources (money to skills, “points” to stats/spells, etc).

And I’m really struggling with evaluating those categories for “d20”, for answering “How good is the d20 engine for computer games”, when a given implementation of the d20 engine could arguably support or not support most any of those.

Hmmm… perhaps that’s the route I should take, actually: does choosing d20 enable you to implement each of those variants? I still need to ponder whether that’s the right question.

[Vahnavoi]

It doesn't matter if it's the right question, because the answer is straightforwardly "yes". All it would take is someone writing the rules engine so you can swap certain character options around easily. This has already been done for some computer games that are open development. Angband roguelike is the best example I can think of from the top of my head. At some point of development, the code was cleaned up, with lot of content moved to easily modifiable text files, allowing creation of dozens of different variants.

If Incursion had similarly clean source code, it could've been basis for similarly expansive list of d20-based variants. The primary reason this didn't happen is that, despite being published for use, the source code and information structure are not as easy to deal with.

[Telok]

I honestly have no clue what "the d20 engine" even means in this context.

Like I can say "Pendragon uses the d20 engine" and be serious because it's throwing a d20 +/- stuff vs a target number, and it was already on it's 4th edition in 1995 before TSR collapsed. There was a Diablo d20 table top that was hilariously bad and would have been complete **** if ported back to the computer with it's rules. You can take freaking Gurps or Champions into using a d20 with just some basic scaling math conversions while keeping all the actual % chances and bell curves the same and call that "using the d20 engine".

So yeah, no clue. The actual dicing for probabilities and character building bits are functionally trivial compared to deciding what actions & interactions you're going to encode for the computer.

[GloatingSwine]

I honestly have no clue what "the d20 engine" even means in this context.

I mean generally if people talk about "d20" in the context of a game engine they mean the one with the trademarked name "d20 System" and described in the d20 system reference document.

[Telok]

I mean generally if people talk about "d20" in the context of a game engine they mean the one with the trademarked name "d20 System" and described in the d20 system reference document.

So the Diablo d20 cluster **** of bad rules? Or some WoW d20 thing? Or just the 3.5 srd? Or a combo of the 3.5 and 5e srds? Or some hacked version of 3e? Or exactly and only what's in the 5e srd? Or some interpretation of AD&D converted to d20+number instead of the assortment of roll over, under, percentiles, etc., etc.?

[Anymage]

The weak form of the question is if just d20+mods>=target number is a good model for a computer game, whether VTT or full on video game. The lack of probability curve and granularity only coming in 5% chunks being core elements. The stronger form of the question will let you pick your d20 based RPG system, whether 3.5 or 5e or whatever else strikes your fancy.

I know there's value to games running in D&D settings based off of D&D rules where the whole billing is that you can play D&D on your computer. However, if WotC wants to focus more on digital products (as we've heard quite a bit about with all the OGL kerfuffle), how well does the current ruleset work in a different medium and what might be good modifications to best fit the new medium. Again, both VTT and fully developed video games are worth asking.

[Tanarii]

Honestly, the bigger issue is TTRPGs are turn based. Modern CRPGs very rarely are turn based. When they're based on a TTRPG, that's usually the number one obstacle to be surmounted, and the primary thing that stops it from feeling like a TTRPG.

Some games have a good middle ground, but they're not all that common.

[warty goblin]

Honestly, the bigger issue is TTRPGs are turn based. Modern CRPGs very rarely are turn based. When they're based on a TTRPG, that's usually the number one obstacle to be surmounted, and the primary thing that stops it from feeling like a TTRPG.

Some games have a good middle ground, but they're not all that common.

I'd say seven or ten years ago most cRPGs were some flavor of real time. But in the last half decade or so the pendulum has definitely swung towards either pure turn based, or turn based as an option.

[Psyren]

I'd say seven or ten years ago most cRPGs were some flavor of real time. But in the last half decade or so the pendulum has definitely swung towards either pure turn based, or turn based as an option.

Agreed - real-time-with-pause isn't nearly as universal as it used to be, and even when it's the default without a turn-based option, modders have been taking it upon themselves to create it.

[Tanarii]

I'd say seven or ten years ago most cRPGs were some flavor of real time. But in the last half decade or so the pendulum has definitely swung towards either pure turn based, or turn based as an option.

Eh, maybe I'm out of touch then. Last I looked it was Divinity OS I / II or go home.

[warty goblin]

Eh, maybe I'm out of touch then. Last I looked it was Divinity OS I / II or go home.

It isn't like there's a zillion of these, and the libe between a cRPG and an XCOM type is often pretty thin, but turn based is pretty common in the genre anymore.

Besides Divinity OS and sequel, Solasta is purely turn based, and also straight 5E in videogame form. Pathfinder Wrath of the Righteous lets you toggle between RTWP and turn based at will, IIRC they patched this back into Kingmaker as well. Obsidian also added turn based to Pillars of Eternity 2, though you have to chose it when starting a new game.

[Rynjin]

Owlcat basically looked at the most popular mods for Kingmaker and integrated like half of them into WotR baseline, yeah.

[Zombimode]

Eh, maybe I'm out of touch then. Last I looked it was Divinity OS I / II or go home.

In addition to those already mentioned:

Wasteland 2 and 3
Encased
Atom RPG
Lost Eidolons
King Arthur: Knights Tale
Bards Tale IV
Avadon 2 and 3
Expeditions: Vikings and Rome
Age of Decadence

Just from the top of my head

And more are in the making.
There are also many RPGs with real time combat. It is quite diverse, actually (which is a good thing in my book!).

[Vahnavoi]

I honestly have no clue what "the d20 engine" even means in this context.

Games like Incursion, Icewind Dale 2, Knights of the Old Republic, so on and so forth, directly port tabletop rules published in d20 System Reference Document under Open Gaming License.

There are plenty of other computer games that overly or covertly roll simulated twenty-sided dice to do one thing or another, including computer games based on older versions of D&D, like Baldur's Gate, Icewind Dale, Planescape: Torment, yadda yadda. But they do not use the d20 system.

[CarpeGuitarrem]

The video game RPG space seems pretty clear on this: going d20 is mostly just useful if you're trying to evoke the D&D brand. There's loads of popular cRPGs that use a completely different system, and I think it's notable that KOTOR, arguably the most prominent d20 cRPG, actively conceals the d20 rolls. cRPGs have been doing their own thing for decades, which has resulted in a wide variety of approaches. The main advantage I see to d20 is feeling like D&D, and the success of cRPGs in general seems to be evidence that there's not really any familiarity boost gained from emulating D&D.

At least in the digital RPG space, the touchstones for feeling familiar are honestly Pokemon and Final Fantasy. That said, Disco Elysium was a good example of a very successful cRPG focused on roleplaying... And it used a very simple 2d6 system with an eclectic list of skills/attributes.