Radius or Diameter?

Circle circumference, diameter, radius

I've been working on refining spell descriptions (again) lately -- for hopefully upcoming expanded releases of the OED Book of Spells and Book of War rules. (E.g., we started testing top-level spells in mass battle play in the BOW livestream sessions the other week.) A couple of recent testbeds brought to mind the question: what's better for expressing the area of a circular spell effect, the radius, or the diameter?

For many years I've been strongly biased towards using the radius, because that's the used in mathematical definition of a circle. Arguably, however, it's easier and more common to measure real-world existing circles via the diameter (given the center is not actually part of the circle or necessarily distinguished; think tires, pizzas, wells, etc.)

Funny observation: Gygax's writing for O/AD&D was amazingly inconsistent on the matter, often flip-flopping for various spells in opposite directions. Starting with the first few spells in the Chainmail list, I see:

  • Chainmail: Catapults/fireballs given by diameter, light by radius, protection from evil by diameter, etc.
  • Original D&D: Fireballs by radius, light by diameter, protection from evil by radius (so, each of example toggles)
  • Swords & Spells: Everything by diameter.
  • Advanced D&D: Everything by radius (as far as I can tell).

I think the Swords & Spells case is interesting, because it gives a big list with all the stats (range, area, duration) for every spell in OD&D in a master list. When I did the same thing for my simulator, I found that things got confusing for a specific reason -- every other shape was being expressed by overall width (squares, lines, cubes, rectangles, etc.), but circles were listed by half-width. So I was getting a bit scrambled comparing entries of "circle-2-in." next to "square-3-in." and remembering that the former is actually bigger (wider). Note this is the case where Gygax gave diameters for everything, and I think this explains why.

The other (and related) case is trying to build templates for area spells in a VTT, specifically Roll20. There's a single pipeline for importing a token image and specifying how big it should be in map-square-units, and that interface asks for the total width (whether the image is of a square, rectangle, circle, etc.). So for my circle areas I was having to do an extra mental step and remember to double the indicated rule dimension for each token. In addition, I'd note that hand-drawing circles, ellipses, etc. in Roll20 and most drawing software I'm familiar with involves drawing and reporting on the bounding box for the shape in question; they don't draw from center to circumference.

Based on these experiences, for consistency with other shapes, I had an urge to switch all the circular specifications from radius over to diameter. But I also thought to ask opinions online, and got feedback like this on the ODD74 forums:

Poll: Radius (17) vs. diameter (0).

Similarly, folks on Twitter were almost unanimously in favor of using the radius. Voting on the Wandering DMs Discord server also went for the radius (with some votes switching from diameter back to radius based on discussion there: esp., targeting and determining casualties for a blasting spell). I didn't bother to ask on an AD&D forum, since those rules do uniformly use radius, so I assume everyone will be habituated to that.

Therefore, I'm taking that as an overwhelming preference among the classic D&D community, and not indulge my momentary instinct to switch things to a Swords & Spells type presentation, but instead keep giving radius like everyone expects.

We're all lucky I didn't find some way to argue for the circumference.


Dragon's Lair

Dragon's Lair cover

I've gotten a chance to play the Dragon's Lair arcade game on my PC (finally in the last week or so).

I can't emphasize how ground-breaking this game was when it showed up in arcades back in 1983 (40 years ago as I write this). Up to that point, we'd only seen 8-bit sprite-based games with digital audio blips. Consider the top games from 1982 (per Wikipedia, "the peak year for the golden age of arcade video games") -- Dig Dug, Pole Position, Zaxxon, Q*bert, Time Pilot, etc. Rendered 3D games were about a decade away at that point.

And then all of a sudden the Dragon's Lair cabinet shows up with Laserdisc technology, and you're playing through a full-on Disney-quality animated movie by Don Bluth & co., experiencing booming professional voice acting, etc. My brain still hasn't recovered from what a leap it was.

For years I've tried to get a PC version working and never succeeded. I think I bought at least two CD versions and each time they were broken beyond usability. This past week I decided to do another search and, amazingly, managed to get a version that actually works. Plus the sequels: Dragon's Lair 2, Space Ace, etc.

So I'm playing through and actually learning how to play and decoding the terrifying puzzles for the first time. An amazing trip.

Here's a point: I'm finding that I don't like the sequels nearly so much. This is not remotely a nostalgia thing because, for budget reasons, I really never played any of them back in the day more than once or twice. So, why this preference?

It's because the later iterations made that classic misstep (to me) of inserting more story into the games. The first Dragon's Lair is essentially a picaresque: the action sequences come in basically a random order, and you never know what's coming next. Part of the play is keeping on your toes and identifying each scene quickly as it starts, so as to engage the right move series. This randomness keeps replayability high, and keep the focus tightly on the player skill in each puzzle as you learn and gain expertise with it.

But then each of the games afterward make the Hickman-esque movement of "this game would be better if it was more like a story you'd see in a book or movie". There are more narrative sequences of people talking when you don't have anything to interact with. More importantly, the sequence of scenes is always exactly the same for every play-through, because it needs to keep on a tightly railroaded plot. I find this has three effects: One, replays get boring faster because of the predictability. Two, it's more likely that you replay parts of the same scene back-to-back because the scene needs to get completed before you can continue. Three, when it mulligans you and just pushes you forward after a failure (death), I find that weirdly more jarring, because the Kenny-like death in the middle of the narrative story seems more lampshaded-incoherent.

This sense is of course consistent with my discomfort with the historical progression of inserting more "story" elements into games. For me, something is lost when the tilty-trap swings more in that direction away from the focus on technical player skill. My partner & I have always rolled our eyes at the narrative cut-scenes in real-time strategy games, as another example. But I think we're in the minority, as it's something I've been fairly well exhausted at debating with people over the years -- and probably more than one guest we've had on Wandering DMs has said things like "RPGs aren't about the gameplay, it's about the stories we make with our friends", which I guess I have to respect, but feel completely different about.