Quote from: talysman;547326I take it that you are *not* asking "which rules are OK to change?" since you've played RPGs for a while and written your own. What I think you're asking is: which changes in retro-clones, tribute games, and retro-spinoffs seem like reasonable changes to fit a given playstyle or setting, and which seem like changes merely to be different?

Yes, precisely, and no, this is not about Arrows of Indra.

QuoteThat question is complicated by copyright concerns. Even back in the day, when people were whippin' up their own knock-offs of D&D, they were doing things like replacing names of ability scores to avoid lawsuits. With the OGL, it's easier to replicate some things, but a lot of stuff the cloners want in their game is not in the SRD, so they are forced to provide disguised approximations of original mechanics.

Ok, so instead of calling it "wisdom" you call it "gnosis", I take it that's an acceptable change to you?

QuotePeople have always changed stuff like hit dice, to-hit mods, damages, and AC, so those are forgivable, even if many times they go a way I would never have gone. I'm infamous for preferring numbers like "1" or in extreme cases "2", and using 1d6 for all melée weapons, but I know other people get more hung up on whether one weapon should do more damage than another, or breaking down combat advantages in more detail (+5 for this, +3 for that.)

The real question is what degree of change is acceptable.  If you're talking about "let's use ascending AC instead of descending", that seems pretty sensible to me.  If you're talking about "let's make it all backward so you have to roll a number, subtract the add the AC value, subtract your to-hit bonus, and then get below a certain score to hit", is there really a point to that kind of thing?

QuoteYou have to change things like wandering monster rolls or treasure/stocking rolls, but I prefer keeping the results as close to the original and just changing the exact dice rolled or mods added, while most others have made more significant changes (like the Swords & Wizardry treasure rolls, which I haven't learned to love. That trade-out process seems too complicated and doesn' seem to make the same kinds of treasure troves.)

When a mechanic *has* to be changed for legal reasons, I think it's reasonable to change die type, mods, target number, and whether it is roll high/roll low, but doing other things may be too gimmicky. Like, if starting gold and equipment required bidding on "wealth cards" that are kept secret until all bidding is done. (Not that I've seen any game do that...)

Technically speaking, no mechanic has to be changed for legal reasons.  Names might have to be, but you can't copyright or trademark game rules themselves.  You have to rewrite them in your own words, but you there's no way that you're legally forbidden from having long swords do a d8 damage, or have a certain condition give you -2 to hit, or for orcs to have AC5, etc.

RPGPundit

Quote from: John Morrow;547552I think Ascending AC is a no-brainer unless you are looking for actual backward compatibility with original D&D editions.

I think moving various class skills such as thief skills and ranger tracking into a general d20-based attribute and level oriented skill system like D&D 3.x is also desirable.

As long as the math works out the same then the only practical difference is that personal preference.

The fly in the ointment with ascending AC is AD&D use of repeating 20s.

Quote from: talysman;547326That question is complicated by copyright concerns. Even back in the day, when people were whippin' up their own knock-offs of D&D, they were doing things like replacing names of ability scores to avoid lawsuits. With the OGL, it's easier to replicate some things, but a lot of stuff the cloners want in their game is not in the SRD, so they are forced to provide disguised approximations of original mechanics.

Quote from: RPGPundit;547637Ok, so instead of calling it "wisdom" you call it "gnosis", I take it that's an acceptable change to you?

That's a complicated topic near and dear to my heart. I was/have been working on my own retro-clone, and one of the ideas I've been toying with is how to *avoid* the OGL. With the OGL, there's no prob using the standard ability names. Without it... well, then it's a matter of guessing how different the names have to be, plus the aesthetic consideration of "does this name change sound too stupid?" Changing "Strength" to "Puissant Might" is probably going too far; for some people, "Wisdom" -> "Gnosis" may be equally too far.

I tried to get help on a couple forums once with examples of pre-OGL, commercial near-clones of D&D that had avoided prosecution, with discussion of how much had changed and how much had stayed the same. No one was helpful, so I wound up trying to do some of the work myself. I compiled a couple tables comparing terminology across multiple old-school systems. I'd copy the tables here, but I don't see a way to do tables in BBCode, so I'll link to the blog entries instead:
Ability Score Names
Other Terminology (mostly related to class and level)
The idea is: if more than one of D&D's competitors got away with using the same name for something back in the day, without the OGL and without legal repercussions, then using the same name now might be defensible. Strength, Int, Dex, Con seem safe; Charisma, maybe; Wisdom, not safe.

Quote from: RPGPundit;547637The real question is what degree of change is acceptable.  If you're talking about "let's use ascending AC instead of descending", that seems pretty sensible to me.  If you're talking about "let's make it all backward so you have to roll a number, subtract the add the AC value, subtract your to-hit bonus, and then get below a certain score to hit", is there really a point to that kind of thing?

Technically speaking, no mechanic has to be changed for legal reasons.  Names might have to be, but you can't copyright or trademark game rules themselves.  You have to rewrite them in your own words, but you there's no way that you're legally forbidden from having long swords do a d8 damage, or have a certain condition give you -2 to hit, or for orcs to have AC5, etc.

You can copyright the expression of a game rule, and you can patent it, although I think very few game rules have been patented, so the latter might not be important. But changing the description, terminology and formatting (tables) for mechanics and rules is pretty much necessary to make the expression of the rule distinct. There's also the matter of "look and feel" lawsuits, which have a legal precedent now, thanks to Apple and Microsoft.

I'm no lawyer, but it is my understanding that things like fair use and the lack of copyright coverage for mathematical formula or processes aren't rights, but are mitigating factors. The court won't throw out a look-and-feel lawsuit over copied mechanics just because mechanics can't be copyrighted, but would consider that factor when trying to decide whether one game is too close to another. But I may be wrong on this point. We'll need a lawyer to weigh in, here.

As you point out, ridiculous mathematical or stylistic gymnastics to cover your tracks aren't a very good maneuver, since ultimately they'll just piss off potential players. Plus, I'm pretty sure if the intent of the change seems to be "disguise the fact that I'm stealing these rules", that will be weighed by the courts as well. If you use the exact same terms as D&D, but change the first letter of each term to "Z", no one is going to be fooled.

Disclaimer: IANAL and the following is not legal advice.

Quote from: talysman;547669You can copyright the expression of a game rule, and you can patent it, although I think very few game rules have been patented, so the latter might not be important.

To my knowledge, it's basically none. The exception is a few gaming components are Patented, mainly odd dice (Games Workshop is responsible for many of these). The other thing about a Patent is as I understand it, you cant stop someone using your patented material, you can only demand a certain fee linked to your profit. If your project is making little profit, I am not sure how it works.

QuoteBut changing the description, terminology and formatting (tables) for mechanics and rules is pretty much necessary to make the expression of the rule distinct. There's also the matter of "look and feel" lawsuits, which have a legal precedent now, thanks to Apple and Microsoft.

I'm no lawyer, but it is my understanding that things like fair use and the lack of copyright coverage for mathematical formula or processes aren't rights, but are mitigating factors. The court won't throw out a look-and-feel lawsuit over copied mechanics just because mechanics can't be copyrighted, but would consider that factor when trying to decide whether one game is too close to another. But I may be wrong on this point. We'll need a lawyer to weigh in, here.

Without going to deep into this, because the lawyer I consulted over the issue deploys sarcasm and irony at me when I broadcast his advice, and starts saying things like as I passed on the information to the whole Internet, he would like me to pay the Internet's fees on a per head basis. Making it look as different as possible will help your case. So personally I would change the lot, a lot of people do not though and only change terms unique to one game line.

QuoteAs you point out, ridiculous mathematical or stylistic gymnastics to cover your tracks aren't a very good maneuver, since ultimately they'll just piss off potential players. Plus, I'm pretty sure if the intent of the change seems to be "disguise the fact that I'm stealing these rules", that will be weighed by the courts as well. If you use the exact same terms as D&D, but change the first letter of each term to "Z", no one is going to be fooled.

Again, as you pointed out its only the expression of the rules you have to worry about, you do not have to worry about obfuscating the maths. So as long as your wording explaining how the rules work is different, you should be golden. So as far as I can tell, Ztrength is fine, as long of you do not then cut and paste the description of Strength from the PHB.

Quote from: talysman;547669There's also the matter of "look and feel" lawsuits, which have a legal precedent now, thanks to Apple and Microsoft.

Actually those lawsuits failed as copyright and trade dress don't protect ideas. Afterwards the industry turned to software patents in a massive way which do protect ideas.

The biggest issue is for D&D clones, other than avoid outright copying, is trade dress. Which was the main reason for 70s era RPGs in changing the names of abilities, spells, etc. Trade dress is the biggest reason that Ryan Dancey and other industry folks felt retro

The OGL of course negates this issues as long you release your game under the OGL.