I'm curious, for those who decided to make an original system what motivated the choice?

And once you decided that, what challenges and advantages did you encounter because of it?

i decided to make an original system because no other system could offer me exactly what i wanted; long, involved combats with quickly-resolved rounds, the ability to express character personality in a very specific mechanical way, the rewarding of playing according to narrative themes by consensus. lots of games had one or a few but not all.

the biggest challenge is making it do exactly what you want is difficult, and you have no idea if it works. or if it only works for you. you're wading through unexplored territory, and no amount of conventional wisdom can prepare you for where you need to go.

the biggest advantage is that you are wading through unexplored territory; conventional wisdom does not apply. it's freeing because nobody can tell you what you should be doing.

I like drilling into an existing system and finding the core of it that I like and then buiding back up. This lets me build a system that does exactly what I need and I have special needs -- certain anxieties while reffing a game and smooth playability in text chat. So my system, which borrows heavily from others, does exactly those things.

I created my own original system (called Battles&Balances) because I needed one for computer RPGs, and those designed for tabletop assume a human GM at the helm, able to improvise, change things on the fly and make value judgements. Things a computer is notoriously bad at. So I made one that allows me to balance things well from the start and be reasonably certain of the chances players have, and also that they can *tell* how they're doing and run away if needed before a lucky roll by an enemy kills them without a chance to react. But I made it to use real dice and everything, because that keeps the design grounded. Plus, it was fun! And as a bonus, if people don't mind the extra crunch they can also play it without a computer, which is good for testing if nothing else.

I decided to make my own system because none of the existing ones were what I personally wanted in a system. Simplistic (to a degree) mechanics, "grounded" combat that's dangerous and messy, focus on creative problem solving instead of just combat/etc, able to be used in any genre.

A lot of the challenges I encountered were when I was in relatively unexplored waters in terms of game mechanics. I'm not doing anything too out there, but it can be a bit of a hassle trying to figure out how well it all works together. 

Perhaps both a challenge and an advantage, trying to create a system that was simple but also very grounded, Very minimalist "simulationist". Creating mechanics that were "realistic" was a bit hard, but also easy in the sense that I wasn't trying to create anything over the top, just find the best way to mimic real world rules.

I'm making two of my own systems for two separate games at the moment, though I'm really focused on one alone. 

Basically, I think that mechanics inform how people play a game . People respond to incentives, and they respond to incentives based on what options exist for their characters. I want to make sure those options tell thematic and interesting stories.

Mechanics form the "words" for the language of a game, and I haven't found any preexisting games that let me speak to players and encourage them to play out certain types of stories. Most languages in the world for games are focused pretty narrowly on combat, and I want to have a language that encompasses more than that but deals specifically with the themes and tone that I want the games I'm making to have. Adapting PbtA, or FATE, or d20 to them would leave the gameplay loops absent from the game without the GM trying to force them in, for relatively minimal payoff for the players. 

i’m really happy with the original system i scrapped together for dark sentencer, my first record collection jam game! it was initially going to be a hack of there is no way out of this arena, but then i realized i wanted to explore character creation more, and hit on the core mechanic of drawing a major arcana card to tell you something about your character that you can build on. i like the element of randomness that comes with using a tarot deck to dictate how the game will go, and using suits to determine the mood of a scene came naturally from there, since each suit already has certain meaning ascribed to it.

I tend to mostly make original systems (and sometimes hack my own systems further) simply because it's the design / challenge space that I personally find to be most interesting, engaging, and enjoyable. It's basically just a preference thing. I find it weirdly fun, and I am not entirely sure why. That said, I did have a good time designing my obligatory PbtA hack, and am pretty proud of it.

I have previously skirted around systems like Shadowrun and Storyteller. From my waaaaay back when in about 4th or 5th Edition Warhammer Fantasy TTWargame... I learned the appeal of “lunchbox of dice” but also the downfall of counting... (I had Orcs & Gobbos, I could easily have 40d6 being rolled).

So when I looked about everyone was loving PbtA, Fate, and FitD systems and well... they didn’t feel very “pulpy” to me. I wanted a bit of “lunchbox of dice” thrill but not so “and now we spend 45 seconds separating d6s”.

So, Beta Maxx got born. Most of the time players wouldn’t be super likely to have 10d10 they are rolling, probably 3-7. So a little bit of lunchbox of dice but not separating out 40d6 into two piles and rolling the second pile, and then...

The big thing for me about the system is the table-addition Traits making the game quite easy to theme/genre modify, and that “fistful of dice” feeling.

I just don't like feeling like I'm being "lazy" or "unoriginal" by using an existing system. Curiously, this is a standard I only hold myself to, and have no problem with other people hacking an extant system for a game, and have in fact played some of those games and enjoyed them.

In most cases, I like using an existing system.  But the system I'm currently working on is a result of frustrations in PbEM and non-asynchronous games.  Either you slow things down, or everything becomes purely narrative.  I'm trying to find a middle ground.

The reason that normally I go with something that's already there is because of my play style- I only mine things in other systems for ideas, as knowing a system, you can really get an idea about it's strengths and weaknesses over time with it.  A new system you have to start all of that from scratch.

I almost always start with creating a new system, because I'm interested in tinkering and experimenting. The games I make usually start with a question about different ways to structure the RPG experience. "What if we have two players control one character?" "What if you use the board game Mastermind to model scientific discovery?" "What if we use this mechanic to model this experience?" etc. Then I build from there the mechanics needed to support that idea.

I usually only use an existing system when the initial question/experiment relates to the system's base system. "What if you used Cthulhu Dark to model time travel?" "How much can I remove or change from this game before it stops being recognizable as a hack of the original?" "If I stick this subsystem from game A onto game B, will that make the experience we want?"

The advantage of using an existing system isn't that it's simpler. It's not. You still should be doing the hard work to understand each component and critically examine it and think about the role you want in the game, just the same as you would have to do if you were making your own game from scratch. But it has the advantage of learning about a different designer's thoughts. Taking apart their game and rebuilding it opens you up to ways of doing things you wouldn't think of on your own.

I didn't start out writing my own system (I mean, I did, then it was a lot of work, so I started hacking instead), but my hack got out of control and I decided to go back and break from compatibility for the sake of internal consistency. So my "BRP hack" is now "inspired by BRP" I guess.

Largely, I wanted something which gave me small character improvements through play (organic skill-ups over time) and a classless framework to build tons of different characters into.

I needed something flexible enough to play merchants and politics, adventures and warfare, investigations and heists - but mechanically simple enough I'd actually run it. So, like most folks who get to hacking, I made a thing that works for me and have set about making it sensible and coherent enough for other folks to use.

I tried using straight BRP/D&D and derivatives with some house rules but it kept snowballing til a system-of-its-own was warranted. That also came with freedom though, because I was able to weave the world's magic into and through so much more than I could just hanging it on existing systems!

I tend to really like settings with their own systems, but I also buy a lot of system-agnostic settings, so /shrug

For me, system design is intrinsically enjoyable, and learning new systems is enjoyable as well, so I like seeing and doing lots of original system design.

For Laser Kittens specifically I had a particular dynamic that I wanted to model -- a kitten building up uncontrollable energy until they just explode, with unpredictable results, but with the ability to shape and channel it as they mature. I didn't see any existing systems with anything similar, so rather than spending a lot of time searching for the perfect thing to hack, I went ahead and designed my own.

-Stentor

When I first got into role playing the group of gamers I played with each ran a different game with a different system. Over the years we tended toward playing more different systems and different games. I never really got into playing one game to the exclusion of others. For me, every game I played was a new system. 

This has influenced by attitudes now as I am writing games - why wouldn't every game have it's own system? It's what I played. I like learning new systems, and I like the way that new systems play with the story experience around the table - allowing or encouraging different things.  

A new setting feels like it almost demands a new system - the system is the architecture through which we, as players/GMs, experience the world and get to tell stories within it. The system gives wings to the setting, defines and describes it by what it allows and what it pushes the players and GM to do at the table. Those are the drivers and advantages in my view. The challenges sit around getting the system to engender the sort of play you want the game/setting to exemplify, and balance, balance is the other challenge! :D

I started running D&D 3.5 in a custom setting based on Garth Nix's Old Kingdom trilogy. It was really fun, but I needed to do a lot of creative work to make the rules of 3.5 fit the setting - change how races work, brand-new classes and skills, etc. When I moved to more traditional fantasy settings, I still saw a lot of bugs in the rules, things that didn't make sense or were just inconsistently designed (The Alexandrian's 'Calibrating Your Expectations' post really opened my eyes there). My houserules got pretty extensive, and when my group switched to Pathfinder and then Numenera, I kept finding things to improve or tweak. I ran LotFP for a year and really enjoyed it, but I also kept adding and expanding stuff as appropriate for my setting and the tone of my games. I did a lot of research and read very extensively in the RPG blogosphere to see what other people had done and why. Eventually, I decided to stop trying to substantially hack these rulesets and write my own; after 5ish years playing and running, I had run and played in a fair number of different systems and knew what types of resolution mechanics I liked and also had a pretty good idea as to some elements I wanted to explicitly incorporate in my game that I didn't see a lot of other systems offer in a meaningful way. I've been running my own system at my table for over a year now, and the rules are very different in a lot of ways than where I started. Some stuff has really worked, some stuff really hasn't. I'm blessed with several very ttrpg-knowledgeable players and some who were brand-new, so I get a nice mix of opinions that have been incredibly helpful to the design process.

I've been working on a new system because I wanted full control over being able to make digital apps and games around it. If you use an existing system, you're having to adhere to a restrictive license telling you what you can & can't do, how to credit the existing work when you are allowed to use it, and it's just a huge headache. Also, most of the existing tabletop RPG systems I've played don't match a video game setting very well. I am new to building a tabletop rpg system from scratch, but I'm trying to come up with something that can be played with pen & paper or as a digital game.