Over the years I've read WB questions that were very generic in nature, and others that wanted the ugly details. A handful prompted my post about running to the patent office because the details would prove to be an enormously valuable commodity.

In my opinion, the reality of worldbuilding is that, generally speaking, worldbuilders shouldn't focus too closely on the details. This was underscored by a recent question: Are there alternatives to mining asteroids/planets for obtaining matter?

Please note that the OP for the linked question is NOT asking for details in any way. It wasn't that which prompted my raised eyebrow. It was the cool quote the OP brought in from We are Legion, by Dennis E. Taylor.

3D printers delivered individual atoms using a number of tuned carbon nanotubes, each sized for specific elements. (...) as you had to place individual carbon atoms, one after another, with zero defect.

We recently hosted a question about near-future limitations to 3D printing. It was interesting to see some of the answers and comments reflecting the wonderful (if not engineering-educated) optimism that the technology can evolve to do almost everything, including replace Star Trek replicators (I'm exaggerating a bit, but work with me 😁). With that question somewhat fresh in my mind, the quote from We are Legion got me thinking. How long would it take to print a 5mm x 10cm x 1m bar of iron?

Keep in mind, we're dealing with just one atom: iron (Fe), so we're already ignoring a massive amount of "reality" for that 3D printer. I also found that I had to ignore "reality" for a lot of other things:

  • How do you hold the atoms in place while you're laying them down?
  • The physical size of the nanotube limits the amount of parallelism that can be applied.
  • The quote says "zero defects...," that's a huge ignorance.

But, given this accepted "unreality" and lack of details, how long would it take? More assumptions:

  • We can parallelize the nanotubes to lay down the approximately 794 billion atoms in a single 10cm line of atoms in a single second.
  • We can similarly parallelize the nanotubes to lay down the entire 5mm x 10cm face of the bar (one atom thick!) in that same second.

Those are both whopping assumptions, but we started with some doozies, so let's move forward. How long would it take?

The problem with 3D printing is that it's working on 2D surfaces. No 3D printer today (or, if I'm honest about it, imaginable within the context of 3D printing today) can structure a 3-dimensional object simultaneously. That means we can optimize the 2D layer — but not the third dimension transport of the print head. So, how long to get our 5mm x 10cm x 1m bar given the speed we can print the single atomic face?

254 thousand YEARS

Getting that bar in just 60 seconds would mean building that single atomic face in just 125 femtoseconds, also known as 8e11 m/s or about 2,600X the speed of light.

Yes, I played fast-and-loose with the construction math for the sake of a cheap thrill... but I couldn't resist. But you can see why Dennis E. Taylor didn't bother with the details about how his 3D printer worked, right? Look at all the details we had to ignore and assumptions we had to make just to get to the one detail that proved the idea is implausible and unbelievable if you look at it too closely.

Question: What advice can we give new worldbuilders about balancing the need for a rule with the details implementing that rule? When does it makes sense to look more closely, and when does it not?

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    $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – L.Dutch Mod
    Commented May 7, 2021 at 19:23

4 Answers 4


I think it should be up to the questioner how much information they need. And it is up to the answerer to decide how much answer to give. No one should decide for the other. They can ask, and you can answer.

We can't say how much information is the right amount as it is not always implied in the question how much the answer will impact their story.

On the other hand, I'm assuming (and maybe I shouldn't) that the questioner has a certain amount of imagination and will "fill in the blanks," as it were, with a certain amount of research and said imagination combined.

I think it serves better to ask for clarification when there is doubt.

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    $\begingroup$ Ultimately, this is the Correct Answer, if for no other reason than the question itself is based on the querent's own opinion. JBH's ideal is a minimalist approach, which I can certainly appreciate; my own approach is to seek more detail from the querent, as I find that qualitatively better answers can be crafted with those points in mind; yet I think we can both agree that a wall of text is too much to bear! All that given, I think you hit the last nail in Dracula's coffin right on the head with this, that it is up to the questioner how much information they need. $\endgroup$
    – elemtilas
    Commented May 11, 2021 at 17:57

I completely agree. More often than not, when building a world the fewer details the better. If for no other reason than that if there are fewer details it's less likely that one detail is going to lead to a contradiction of another.

For instance, if you tell me that there are giant monsters terrorizing the Pacific Rim and we must pilot giant robots defeat them, explaining the details of the metallurgy required to get the grain structure of the metals to make a giant robots structurally sound enough to punch the monsters in the face, will kill my immersion faster than you can say Young's modulus. While I personally love hearing about cool advances in material science unless you're a researcher publishing a new finding, going into that level of detail will, distract me from the story you're trying to tell me. That is assuming that you didn't introduce any inconsistencies in your world by adding the extra information.

Unfortunately we're not here to give advice on how to create a good work set in a world. We're here to help people build their world. We currently don't have a good way to ask "Are you sure you need to explain x?". That question isn't about building the world but what they're going to use the world for. Perhaps they're writing a story about the evolution of anthropomorphic beings with scenes being set over millennia. Then they definitely need to explain how their animal-people evolved. On the other hand if they're writing a story about a group of animals who work in a coffee shop together and the evolving drama of their interpersonal relationships, explaining how they evolved will detract from story.

I don't think there's a way for us to create a policy about this that doesn't turn into subjective gatekeeping of questions. I still think we should do more. We could try to create a culture that tries to emphasize considering how much explanation is sufficient in our answers. Some ways we could go about this include.

  • When answering a question, if the specifics of a detail doesn't matter, emphasize in your answer that it's probably ok to handwave a particular detail.
  • Bring up the risk of too much detail in comments and answers to encourage people to think about if more explanation is needed.
  • If someone is asking for some highly technical detail, (Such as the case with the many questions we have about the orbital mechanics of specific configurations with planets) ask clarifying questions about the level of detail. Perhaps the correct answer from a worldbuilding perspective is "You don't need to explain this, because X". Personally I'm not bothered that having the suns on Tatooine impossibly close together in the sky. Luke staring longingly off into the setting suns was a magnificent scene.
  • Ask clarifying questions on posts asking how detailed do they want answers to be. Are they looking for realistic sounding technobabble or will the details be closely interrogated in works set in the world.
  • We may want to revisit meta-tags like hard-science and require people to clarify exactly what details they're looking for in their questions rather than relying on a tag.
  • Update the site's help center text to emphasize that we're here to help with figuring out what you can get away with handwaving.
  • $\begingroup$ I wholeheartedly disagree. When building the world it's important to get all the details you need. BUT never put them into the story unless they're essential to the story. The details help you make consistent rules, but the reader doesn't need to be told what those rules are. $\endgroup$
    – Separatrix
    Commented May 11, 2021 at 7:36
  • $\begingroup$ @Separatrix I don't see how what both of us are saying are incompatible. Could you clarify what you disagree with? We both think that there are details that you need, details you don't need, and details that you shouldn't burden your audience with. $\endgroup$
    – sphennings
    Commented May 11, 2021 at 12:40
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    $\begingroup$ As the author building the world, the details are critical. You have to know what they are to stick to the rules. There are no details you don't need, but there are details that you don't need to communicate. If a thing exists or an event occurs it must have a full set of rules in the author's notes so that it can do the same thing every time. When telling a story that's when the fewer details are better. It's that key opening bolded statement that you make $\endgroup$
    – Separatrix
    Commented May 11, 2021 at 13:53
  • $\begingroup$ I can almost agree 100% with what you're saying. I think that when building a world some details are critical, and others may not matter. It seems where we disagree is the amount of emphasis we place on ignoring irrelevant details. I think that as long as we're not gatekeeping worldbuilders that want lots of detail, it's ok to philosophically disagree about what the right amount of detail is. $\endgroup$
    – sphennings
    Commented May 11, 2021 at 15:17

I wonder if by saying this:

In my opinion, the reality of worldbuilding is that, generally speaking, worldbuilders shouldn't focus too closely on the details.

you are trying to impose your views and values on the entire community. You bring one decent example demonstrating that sometimes asking for details is unproductive. However, does it apply to everything?

Different audiences and different creators prefer different levels of detail. Perhaps, you are one of those readers who skip lengthy descriptions of minor details. However, there are plenty of Jordan fans who praise his works and the amount of attention (and words) he gave to clothing, hairstyles, scenery, etc.

Details are what makes fictional worlds real. And details are also what ruins fictional worlds. It is very easy to get the big picture right, but it is extremely hard to get all details right. Just recall all those zombie films where character never run out of bullets or gasoline no matter how much time has passed since Day 0. Or think about all those fictional societies that 'develop' cultural traits and patterns that are unsustainable and/or defying everything we know about humans.

Should not a stack dedicated to worldbuilding help worldbuilders get details right?

Some additional thoughts:

  1. It is not your or my place to make decisions on behalf of the questioner when it comes to details they need. It is the prerogative of the creator of a world to choose what to include and what not to include in their world and how deep they want to delve into specifics.

  2. People do not know what they do not know. One's understanding of a subject may not be deep enough to be capable of discerning which details are important and which are not. It is always better to leave these matters to the creators themselves.

I also want to mention that lack of details leads to really bad answers. For example your answer to the question about loss of knowledge after the apocalypse. You ultimately end in self-contradiction and refute your own thesis that it's very hard to lose knowledge. A brief summary of weak points in your answer is below.

I'm afraid most of the answers you've been given make some serious assumptions that are, frankly, false. It's very, very hard to lose substantial information — even after a nuclear apocalypse.

Human history is full of instances where most of the information associated with a specific human culture has been lost almost completely. The loss of information (for example, traditional crafts and building techniques: Kimono-making, traditional oven building in Russia, organ building in Europe to name a few) happens today as well. But perhaps you do not regard dying-out technologies as substantial enough. You could've provided details explaining what substantial information means, but you did not. And as such your statement is false.

I apologize that this seems trite: but generally speaking, people aren't stupid. Almost everyone who survived the apocalypse would be literate (can read and write) and would pass that along to their children. Why? Because knowledge is power.

First of all, literacy is not education. It is just an ability to write and read. Secondly, historically high levels of literacy were associated with the existence of robust educational systems and/or religions that require the ability to read scriptures (e.g. Islam). Thirdly, there are no historical examples of high levels of educational attainment in poor societies. Education and pursuit of knowledge require full bellies and spare time.

Not necessarily knowledge of, say, quantum physics... but knowledge of business, fundamental mathematics, mechanics, civil and structural engineering, electricity, etc.

So, how much knowledge is going to be lost? You also do not mention art, philosophy, history, technological know-how, languages, and many other areas. Are these not knowledge? Or do you imply that art, history, and philosophy are somehow hard to lose (your premise is that knowledge is very hard to lose)?

The world is a very structured place. Schools would quickly reform because, per #1, people generally aren't stupid. You'll have plenty of people who know that failing to train the next generation is a really bad idea.

You make a good point here. However, you miss one important details: Next generations will be trained only in things that are necessary and sustainable. Farmers won't train painters, writers, or philosophers. A lot of non-essential knowledge will be lost.

We're addicted to technology. Yes, humans can figure out how to "live off the land." But realistically, you'll have people getting generators, computers, and the lights working very quickly. Even small town hardware stores have generators ready to sell and you can make a passable biodiesel fuel out of cooking oil (and cooking oil comes from both vegetables and animal fats...).

How long the generators will last? This is a very important detail. Can your generators last long enough to repair/rebuild infrastructure? Also, are your generators enough to power data centres?

Even a nuclear apocalypse wouldn't destroy every library in every city (and university, college, school...). Books will be everywhere. In homes, in stores... everywhere. The world wouldn't lack for books unless your story drives a reason for those books to be destroyed.

Do books contain ALL knowledge? No. One of the most obvious examples is practical knowledge and skills. Take for example cooking. You can learn theory from books. Books can even give you precise recipes. However, if you want to learn cooking skills an expert's guidance and supervision would be the most effective. Of course, you can learn things on your own. However, how much time and resources would it take? Is it even feasible in a post-apocalyptic setting?

What kind of books a school library has? Well, it has various textbooks and some small collection of classics. It might have some odd books as well. However, this kind of library contains only a small fraction of knowledge. Moreover, it is often simplified (textbooks) and/or ideologically biased (because schools are not unbiased).

How many small towns and colleges have decent book collections? Very few. Books are expensive and troublesome to store.

You also mention stores. Stores do not stock books that are not popular with their customer base. Therefore, their stocks are representative of the interests of the local population rather than the accumulated human knowledge.

There is one more important detail in regard to books. Modern books are fragile and modern libraries rely on a controlled environment to preserve books. If post-apocalyptic conditions are unfavourable a lot of books will be partially or fully damaged by moisture, rot, mould, etc. Most of the frequently used books (like repair manuals) will not last long because they are not meant to withstand extensive wear.

99.99% of the technology we use today was invented in the last 150 years. This is incredibly important to understand.

You are missing an incredibly important detail: The technology and industrial expansion of the past 150 years were not built from scratch or on the ruins of the previous civilisation. They relied on industry, expertise, knowledge, supply chains, and resources that already existed and properly functioned.

If your apocalypse was so thorough that it destroyed 90% of the population (leaving some 770 million people, at least half of which are adults...), you'd still have so many people with so much knowledge in their heads that it would be believable to have everything back to today's standards in 150 years.

770 million is a big number, even an impressive one. However, without knowing details related to demographics, population density, the scale of destruction, specifics of post-apocalyptic social structures, and state of communications it is just a number that does not have much predictive power.

If all major population and industrial centres are destroyed (which is the most likely outcome of a properly planned nuclear apocalypse) the majority of specialists required to rebuild just technology to today's levels will be lost. A lot of specialised knowledge will also be lost.

Yes, you have the radiation problems... but you have people with modern medical knowledge and medical supplies literally everywhere. You wouldn't have the mortality problems of the middle ages.

This situation will last for the first couple of decades. What happens after old doctors die and supplies exhausted will depend on the success of reconstruction. If people do not manage to restore the pharmaceutical industry and train medical personnel high mortality will be back.

SciFi loves the idea of a Mad Max-style apocalypse, where whole groups of people have somehow regressed and access to knowledge is mysterious. In reality, the world is swimming in knowledge. Oh, we might lose a lot of the things that don't affect everyday life (like astrophysics and quantum physics) and the destruction may have made it difficult to bring the highest tech back quickly (like nanometer-geometry computer chips).

Here you finally give some details and you immediately state that 'a lot of things will be lost'. Isn't it self-contradiction?

But electricity, chemistry, mechanics... and books... would all be in use from 10 seconds after the bombs hit. And there's so much stuff available that resources would exist for years... even decades....

The real question is how long it will last. And the answer to that will depend on details.

Do not underestimate just how much knowledge is in the head of the average 35-year-old person (much less the 60-year-olds...). Your real challenge is justifying its non-existence. That will be a contrivance, not an inevitability.

It really does not matter how much knowledge a particular individual has if they cannot pass their knowledge onto others.

Oh, one more important detail: your answer focuses on the state of affairs immediately after the apocalyptic event, while the question asks for a timeline or future events. You talk about the future only once (suggesting that we can go back to current levels of technology in about 150 years) but you provide no valid support for your statement.

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    $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – L.Dutch Mod
    Commented May 7, 2021 at 19:23
  • $\begingroup$ It was a pleasure to read the answer, it can be improved/expanded a little in few places, but otherwise perfect, lol $\endgroup$
    – MolbOrg
    Commented Jun 4, 2021 at 16:55

The details are critical to the author

but should never be in the story unless they're going to trigger a plot point. So what that it takes 254,000 years to make a short iron bar. Call that 10 seconds and it's now one of the rules of your world. You have an amount of time it takes to build a structure, a fortress, a warship. That's what the handwavium is for. It's also so you can avoid explaining the details of exactly how it's done. However that's for one specific type of story. In this type of story every detail is critical.

How fast is the USS Enterprise NCC-1701-D?

People spend hours on the internet disputing this particular detail, the scale its given on doesn't correspond with anything much in the real world, but that's deliberate, it's for another specific type of story. In this type of story the technology only exists to give plot points, how it works is irrelevant. It's all handwavium, and like wizards, the Enterprise always turns up exactly on time for its role in the story, never too early, never too late.

It's not up to us, answering questions, to decide how much of the detail goes into the story, that's up to the author. We can suggest that it's avoided, but that really comes down to our own tastes in such tales. Do you prefer gritty human interactions in STL generation ships where you're stuck with the same people for years and the engines are slowly decaying, or shiny warp driven planet of the week and alien of the day where the technology just works except when it doesn't.


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