We have an unwritten rule that questions about commercial worlds (e.g. Star Wars, Star Trek, Babylon 5, etc.) should be asked on the Science Fiction & Fantasy stack.

Or we might have one. That's the problem with unwritten rules.

Question: Therefore, I'm seeking consensus concerning whether or not we should officially allow or disallow questions about third-party worlds.

A third-party world (also known as a "commercial" world) is defined to be a world that is not owned by or protected under copyright by the individual asking the question. For the purpose of this discussion, third-party worlds made available through any open-copyright (such as Creative Commons) are still considered "third-party."

Policy on Science Fiction & Fantasy

Any question that is asking for an answer within the context of a fictional universe, even if that question requires real-world science information, is on-topic. … Questions which are explicitly asking for an out-of-universe explanation of the science from a work of science fiction or fantasy should be off-topic. (Source)

This opens up the possibility of asking for out-of-universe explanations of third-party worlds on Worldbuilding. However, there are some pros and cons.


  • It expands the number of questions people may bring to our stack.
  • It increases the visibility of our stack to search engines (e.g., "Star Wars" is mighty visible).


  • It might (and probably does) duplicate what's going on at SciFi.SE (and others, including RPG.SE and Movies.SE).

  • Answers provided on WB.SE may not express the "canon" of that third-party world, potentially opening up unwanted comment discussions.

  • Would invariably create a list of tags identifying the third-party world, the rules of which should (must?) be followed for the purposes of answering the question.


  • I suspect the majority of questions will be requests to explain in-universe eccentricities. In other words, a world isn't actually being built. It's merely an effort to sate the OP's curiosity.
  • OPs don't have control over the world the question refers to. In other words, in the worst case, we might be participating in copyright infringement. (I consider that an outlandish worst-case as fan fiction has some protection. Some.)
  • We sometimes see questions (like this one) where the source of the question is fairly obviously a third-party world. Along with a clear Yes/No, it would be nice to comment on whether or not "I'm borrowing their idea for my world" questions should be permitted. If you think this bullet should be its own question, please indicate so in a comment.

Relevant Meta Questions:

There are basically none. The idea of third-party worlds are mentioned in this answer to an unrelated Meta topic and this answer to a barely related Meta topic.

Example Main Questions

Oddly, there are few Star Trek examples. It appears OPs do a much better job of asking "using this Star Trek idea as an example, how could we...?" instead of, "How does this in-universe idea work?" Curious, that. I wonder if I could get some grant money to study the differences between Star Trek and Star Wars fans?

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    $\begingroup$ For the record, this is the current consensus on SF&F as to what's on-topic there, if we want to avoid stepping on anyone's toes (although there's nothing wrong per se with a question being on-topic on multiple stacks). $\endgroup$
    – Cadence
    May 12, 2019 at 23:37
  • $\begingroup$ @Cadence that helps! I'll formally add it to the post. $\endgroup$ May 12, 2019 at 23:40
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    $\begingroup$ There is certainly a big difference between using an existing IP as an example, and outright asking about an IP that is not owned by the asker. While the former seems more than acceptable, I tend to agree that the later is very much off topic. $\endgroup$ May 13, 2019 at 0:37
  • $\begingroup$ I think Star Trek are more genre-aware, as they tend to be very tongue in cheek about questions. Example: worldbuilding.stackexchange.com/questions/63587/… (by the way, this question, and the answers, were both hilarious and informative) Although I think you're right that these kind of questions belong to sci-fi & fantasy, I also personally think I will miss questions like this. Not the Star Wars ones, though. $\endgroup$ May 14, 2019 at 8:11
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    $\begingroup$ In the example of worldbuilding.stackexchange.com/q/146866/40609, it's similarities to a starwars process do not make it less of a world building question. Starwars cannon does not care if you can carbon freeze a person in real life, a reality check on sci-fi processes are certainly the kind of question we handle here all the time. $\endgroup$
    – Nosajimiki
    May 14, 2019 at 16:00
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    $\begingroup$ @Stormbolter: I’m the OP of that question, and I genuinely wasn’t asking about Star Trek. I was asking about a sci fi world that was a parody of Star Trek, which is a crucial distinction. See here for the meta discussion that generated. $\endgroup$
    – Joe Bloggs
    May 14, 2019 at 16:15
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    $\begingroup$ I'll save you the trouble of doing a study; Star Trek usually does a pretty good job of explaining its tech/phenomena/etc, even if a lot of these explanations are handwavium. As a result, most questions it have already been answered. $\endgroup$
    – The Daleks
    May 2, 2020 at 2:19

5 Answers 5


This site is for questions about building worlds, not questions about how others' worlds work. Now very few ideas are completely original, so your world might use elements from, or derived from, other worlds, but there's a key difference: If you ask "how does a lightsabre work in Star Wars", the only authoritative answers come from the Star Wars canon. If, instead, you want lightsabres in your world and ask "how can I power my lightsabres given (constraints)", that's a worldbuilding question that will likely get answers that have nothing to do with the Star Wars canon.

Ask questions about your world. If you've borrowed ideas that's fine, but the focus is on your world, not what another author intended.

In this case there's another site that can take the kinds of question you want to ask, which is handy. My answer here would be the same even if SciFi.SE didn't exist.

  • $\begingroup$ While I support this answer I think this makes it abusable. Instead of asking, "How does a lightsabre in Star Wars work" I just ask "How can I make a lightsabre work in my world". These question focuses on removing a part of a third party world and implementing the laws of that third party world in another world. It would be more fitting if the OP were to explain why a certain part of the world they are copying doesn't comply with the rules of their world, because sometimes the answer is, thats just a part of the world and how it works. $\endgroup$
    – Shadowzee
    May 13, 2019 at 6:54
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    $\begingroup$ @Shadowzee they'd have to ask a lot more than just "how can I make it work", though -- they'll have to tell us about their world, and about the important properties they want to emulate versus things they don't care about (maybe it turns out you can have orange lightsabres but not red ones, or whatever). In the process of doing that they're probably deviating from the original setting, so "how they work in Star Wars" might not even be an answer to the question. Maybe I'm splitting hairs, but I want the focus to be on your world, even when you're stealing cool ideas from other worlds. $\endgroup$ May 13, 2019 at 15:04
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    $\begingroup$ @Shadowzee If my world is an exact copy of the Star Wars universe in every detail except that I want my lightsabers to not be space magic swords, is it not a new world? $\endgroup$
    – Joe Bloggs
    May 14, 2019 at 16:10
  • $\begingroup$ @JoeBloggs Pretty sure its not a new world. But if you want to do it, I'll let you argue that with Disneys lawyers. I'd also like to add that In the Star Wars universe, light sabers are not magic space swords. They are real weapons in the Star Wars universe. To say they are powered by magic implies that the core technology it relies on is also powered by magic. $\endgroup$
    – Shadowzee
    May 15, 2019 at 0:27
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    $\begingroup$ @Shadowzee Kyber crystals qualify as applied handwavium in my book. AKA magic. A ‘real world’ lightsaber would have completely different properties (as we saw in the question on real world lightsabers) that would have a material impact on the rest of the world (nobody would use a power hungry magnetically confined plasma loop as a weapon. Why would anyone do that?) $\endgroup$
    – Joe Bloggs
    May 15, 2019 at 6:25
  • $\begingroup$ @JoeBloggs But you aren't using the 'real world'. If your Kyber Crystals operate in exactly the same way 'Star wars' Kyber crystals work, then your light saber can also work exactly the same way in your cloned world. The lightsaber question is a poor example of abusing this system. A better example of abuse would be how to recreate the force in the real world. You can't...unless you also handwavium and at that points its just handwaviums all the way down. $\endgroup$
    – Shadowzee
    May 15, 2019 at 8:02
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    $\begingroup$ @Shadowzee: Which is exactly why I used the lightsaber as my example. A world in which there are no handwavium kyber crystals and people want lightsabers that operate according to the known laws of physics is not the same world as the Star Wars universe. It wasn’t an example of how to abuse the system, but an example of how something that might look like abusing the system is actually valid worldbuilding. $\endgroup$
    – Joe Bloggs
    May 15, 2019 at 9:45
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    $\begingroup$ Not just SciFi & Fantasy but any commercial world. As in the huge number of questions based on D&D (which has its own site): asking about a wizard's ability (perk, feat, etc) per D&D rules then ask on RPG.SE. Asking how could my wizard use an ability based on this D&D rule? - it could be on topic here if it meets WB requirements....and, in fact, several questions exist like that here already. $\endgroup$
    – LinkBerest
    May 19, 2019 at 18:45

I think I need to challenge the entire premise of this question.

I don't care if your question is about Star Wars, Star Trek, The Forgotten Realms, or something completely out of your imagination.

I care whether you are:

  1. Building a world
  2. Building a world
  3. Building a world

That's it. Is your world based on Star Wars, Star Trek, Tolkien? Etc. That is irrelevant. What matters is that you are building something.

If you're creating a new world in the Star Wars universe, or a new village in the Forgotten Realms or a new continent in your own unique setting then that's all cool. You're Worldbuilding.

If on the other hand you are asking about established canon of any of those worlds then that is off topic. It is not Worldbuilding.

Questions about existing fictional settings are more likely to fall into the second category than questions about a new setting. That is a problem with the question though, not about the setting.

  • 3
    $\begingroup$ Cannon is the magic word, if knowledge of cannon is required then it's almost certainly not for us. $\endgroup$
    – Separatrix
    May 13, 2019 at 10:25
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    $\begingroup$ @Separatrix I still disagree. If you are writing star wars fan fiction and creating something for that fan fiction (or even if you are a professional author writing a new official star wars book) and you are creating a new world that world may involve knowledge of cannon while at the same time being a valid worldbuilding exercise..... It really all just comes down to two things...is it about building a world...and is it a good question (i.e. too broad, opinion based, etc). So long as both those are true we are good to go. $\endgroup$
    – Tim B
    May 13, 2019 at 11:08
  • $\begingroup$ I think we need some specific examples to bounce around. I'd say requiring knowledge of cannon means you're building in someone else's world, so questions bound by those rules don't apply here. There's nothing preventing the world from being bound by those rules but working on other unrelated or unbound aspects of it. $\endgroup$
    – Separatrix
    May 13, 2019 at 11:19
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    $\begingroup$ This answer has always been my take of how things work. I've answered questions about commercial worlds with ideas that would be too far fetched for them to drive a point. $\endgroup$ May 13, 2019 at 12:38
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    $\begingroup$ I’d argue that an awful lot of questions on this site (almost all, in fact) all copy some points from the same source material: our actual world. The distinction between physics and world building lies in how much new (or at least not noticeably identical) material is brought to the question, so too with sci-fi (or history). $\endgroup$
    – Joe Bloggs
    May 14, 2019 at 16:01
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    $\begingroup$ @Separatrix: A set of commonly accepted works is a canon with one n. A cannon with two ns is a weapon. $\endgroup$
    – AlexP
    May 14, 2019 at 17:42

As long as the answer does not require you to provide information from cannon to be correct, it is fine. Also, if the question requires you to understand cannon for context, it should be something that can be simply looked up without requiring an in depth understanding of the source material. In the case of the OP's example, we do not need to understand how Starwars cannon would answer this question to be able to derive scientific speculations about how the process could be explained in a new piece of work. Nor, do we need to watch an entire star wars movie to get an idea about what carbonite freezing is. If they wanted the George Lucas answer, then the sci-fi exchange would be preferable, but since they want a reasonable explanation, then sci-fi exchange is probably a very bad resource for them.

Examples of questions that are not world building:

  • How did the Hulk get his powers?
  • What are the properties of Mithril in Lord of the Rings?
  • Can Adeptus Mechanicus make new machine spirits?

Similar world building questions:

  • How could you make a person as strong as the Hulk?
  • How could one make a Mithril like alloy similar to what is described in Lord of the Rings?
  • Could Adeptus Mechanicus actually be able to program through rote memorization of chants without understanding the concepts of programming?

The first set of questions have right or wrong answers based on their commercial fiction sources that already exist so there is no world building. The second set of questions use commercial fiction sources for reference, but the answer are still world building in nature. If a person wanted to make a believable world with a Hulk like being, blasting joe-blow with radiation is not a good answer; so, other exchanges would be less helpful than asking it here.

  • $\begingroup$ From the second set of examples, #1 seems sketchy. Since the Hulk appears to have power=plot or power=whatever-current-author-wants, then the only way to have somebody as strong as the Hulk is to handwave it. #3 also seems like something about in-universe lore. Or extrapolation of that lore. Or maybe even straight up fan-fiction territory. I'm not familiar enough with WH40k to know if it has addressed this but what I know is it's not a WB question. In fact, it doesn't seem very different to the other #3 - it's asking for the same type of information - in-universe explanation. $\endgroup$
    – VLAZ
    May 15, 2019 at 18:39
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    $\begingroup$ #1b uses the Hulk as a point of reference. While his strength is inconsistent in lore, it gives a general order of magnitude that most people are familiar with. The question is not much different than asking if a person can be as strong as an elephant. Even though I don't specify or care about the elephant's age, gender, species, size, or general health it gives enough info to make an approximate and informed estimation. It's not an ideal question, but still WB. $\endgroup$
    – Nosajimiki
    May 15, 2019 at 19:30
  • $\begingroup$ #3b uses Adeptus Mechanicus as an example, but them being Adeptus Mechanicus does not impact the answer at all. The core of the question is about if it is possible to program through rote memorization without understanding the concepts of programming. You could replace Adeptus Mechanicus with a more generic term like "a techno cultist" or even "a person" and the question is still asking the same thing. Again, not saying these examples are ideal questions, just that they are WB questions. $\endgroup$
    – Nosajimiki
    May 15, 2019 at 19:38
  • $\begingroup$ I really don't see how #3b is wholly different to #3a. Sure if you replace everything that links it to #3a, then it's not but...then it's not even #3b. As it stands it is asking for how an existing group in an existing IP would do something within that IP. Removing any references to the IP is better but that's not the question you've presented here. I'd expect the question with #3b's title over at SciFi.SE or RPG.SE - not sure which is a better fit. $\endgroup$
    – VLAZ
    May 15, 2019 at 19:42
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    $\begingroup$ Here is the problem with that: SciFi.SE or RPG.SE answer according to cannon. In 40k cannon, the answer is a handwavy hard "yes". In WB.SE, we generally question the possibility of outlandish scenarios. If an author working for Games Workshop or a fan fiction writer wanted to improve the believability of Adeptus Mechanicus through a reality check question, then they would have much better luck here since we dismiss the fictional cannon and approach the problem as a matter of facts. $\endgroup$
    – Nosajimiki
    May 15, 2019 at 19:57


In reviewing the pertinent Help Center documents for WB.SE & SCI-FI/FANT.SE, I think there is support for this position. Worldbuilding is for "designers, writers, artists, gamers and enthusiasts to get help creating imaginary worlds" while Sci-Fi/Fantasy is for "questions targeted towards science fiction and fantasy enthusiasts. This includes questions about ... (inter alia) setting explanations".

The query under consideration I think is clearly asking about a Star Wars phenomenon, even though the OP was trying to be clever by cloaking that fact within a rather flimsy attempt at providing "worldbuilding context".

My Take

While I understand the desire to increase WB's footprint in the search engine game, I would take the above facts to indicate that WB is designed for people engaged in making their own worlds; while SF/F is designed for people engaging with commercial or literary entities. Therefore, I think your policy proposal (as far as is goes thus far) has a sound basis.


I don't know if the rule is written or unwritten, but it seems that recent queries regarding invented languages have been invited to move over to the invented language stack. Rightfully so, even though language is at the heart of culture and culture is at the heart of creating secondary worlds full of people! The fact is, there is a subgroup that specialised in language, thus I'd say it's best practice to shift such questions over to that stack.

Likewise with commercial worlds. There is a forum that specialises in works of fantasy and sci-fi (novels, short stories, animes, movies, television programmes, etc) and the worlds they happen in. I'd say it would be best practice to move such questions over to that forum. Though I suppose WB would have to ask first!

I'm Borrowing This Idea

Of course, borrowing ideas is nothing new in art. What we'd have to distinguish is whether or not the OP is really and truly borrowing something for her own work, or whether she's just curious about how something in SW works and is tacking on some world building context veneer in order to sneak past the censors.

Make it clear that "I'm borrowing this idea" is a valid reason to bring up a phenomenon that occurs in a commercial world, but that worldbuilding context needs to be quite robust in order for such a question to be accepted. In other words, something like "XYZ happens in the SW universe, and my plan is to borrow that phenomenon while changing this and this to that and that."

Possible Concerns:

How far is too far? You've given SW and ST as example of "third party worlds" whose questions we might consider shunting to SF/F.SE

But this begs the question, what actually ought to constitute a "third party world" for the purposes of the new policy?

  1. Star Wars --- I guess that's obvious
  2. Star Trek --- I guess that's also obvious
  3. Avengers, X-Men, Discoworld, Middle Earth, Dr. Who, BSG --- okay maybe?
  4. What about non-commercial third party worlds? D&D is kind of a grey area in that there are published guidebooks and so forth, but also a lot of individual creativity.
  5. What about fan fic worlds? Worlds that build on one of these better known places, say a world that is an extension of Middle Earth?

In other words, how big would it have to be in order to get bumped?

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    $\begingroup$ but that worldbuilding context needs to be quite robust in order for such a question to be accepted I agree with this. If the OP can provide enough info about their own world that we can use the example to answer the question from the perspective of the OP's world, then we're on-topic. Without the framework of the OP's world, it's off-topic. $\endgroup$ May 13, 2019 at 1:06
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    $\begingroup$ Marvel, DC Comics, Dr. Who/BBC... these are all third-party worlds enjoying copyright protection. I'm advocating the basic definition, "if it's not your world, don't ask about it." Fan fiction is still based in the third-party world, so it's not the OP's world, IMO. I think it's been pretty rare to get RPG-world questions. 99% of the time it's simply "medieval fantasy." Can you remember a Q that was strictly a D&D (or its ilk) question? $\endgroup$ May 13, 2019 at 1:08
  • $\begingroup$ Just trying to foresee as many rakes in your path as I can! I can't think of any DnD queries, but that doesn't mean there have never been nor that twenty won't show up a fortnight after this rolls out! That leaves fan-fic worlds. $\endgroup$
    – elemtilas
    May 13, 2019 at 2:05
  • $\begingroup$ I've seen questions about RPG settings, although I don't have links handy. The worldbuilding.stackexchange.com/questions/tagged/rpg tag only has 27 entries but I expect most questions aren't tagged for it. $\endgroup$
    – Tim B
    May 13, 2019 at 9:20
  • $\begingroup$ A search for "rpg" worldbuilding.stackexchange.com/search?q=rpg gives 569 results $\endgroup$
    – Tim B
    May 13, 2019 at 9:21
  • $\begingroup$ @TimB converting your search to include is:question reduces the list to 159. A quick glance through that list seems to confirm a suspicion of mine: 99% of "rpg" questions aren't asking about specific third-party worlds. They're along the lines of, "I'm building this RPG and need...." I looked at several such questions and couldn't personally identify the third-party world (if there was one). RPGs are the grey area for this question because a fair number of people use things like GURPS for the gameplay rules and otherwise build unique worlds. $\endgroup$ May 13, 2019 at 13:53
  • $\begingroup$ "I can't think of any DnD queries" there were two questions I noticed in the HNQ a couple of days ago - one was from RPG.SE asking "How can a lich disguise as a human without magic" and another from WB.SE asking "How can a skeleton disguise as a human". I didn't click on them but I am fairly sure they were about exactly the same situation. I suspect it started as a lich question and was then generalised as skeleton. $\endgroup$
    – VLAZ
    May 13, 2019 at 16:39
  • $\begingroup$ Huh, I suppose I was wrong. Found the questions What is the best way for a skeleton to impersonate human without using magic? posted on the 10th of May at 9 in the morning How can a Lich look like a human without magic? posted on the 10th of May at just about 7 in the evening. Weird. $\endgroup$
    – VLAZ
    May 13, 2019 at 16:45
  • $\begingroup$ @VLAZ, also would like to point there is a manga that features exactly the same issue (mangarock.com/manga/mrs-serie-100066731), so unless it explicity declares any kind of source canon, it can be difficult to know if it's based on an universe or it's a worldbuilding issue. $\endgroup$ May 14, 2019 at 8:19
  • $\begingroup$ 28 questions if you just search for dungeons and dragons - not a lot but some (103 if you just search for it showing answers like to reference D&D even if its not mentioned in the Q :) @JBH - none recently but several less then 6 months old & one from January which is really based on D&D rules (literally designs dragons based on it) $\endgroup$
    – LinkBerest
    May 19, 2019 at 19:06

The Mephisto transformation

My hypothesis is:

If you fill off all the serial numbers from the question, add the relevant information from the world, it's about, and the result gets upvotes and answers, then it should be fine.

Star Wars has no internal consistency in terms of rules, especially since what is and isn't canon changes when The Rat nods one of her heads.

Asking about hard-SF or taking a singular idea into a defined context. For instance, a question like: "In a realistic ( ) setting, what would be the best cover for the witch's house (from Hansel and Gretel) to prevent it from rapidly decomposing whilst remaining safe for human consumption?" should be all fine if the transformation can be completed.

For those occasions, whether the answer can be derived directly from canon or not, is a deciding factor, as if it can be solved by x fanboyism, where x != any scientific field, it's off-topic here.


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