Monday, August 18, 2008

A Simple Algorithm for Generating DCs

As has become something of a habit for me lately, I wrote an adventure on the plane ride home from GenCon. Lately, it's rare that I have 3 to 4 consecutive hours to do anything other than (sometimes) sleep.

I'm a big believer that laziness is the mother of insight. Many folk see a tendency toward sloth as a bad thing, but if not for sloth, we'd still be living in caves, hunting brontosauruses, and hiding from thunderstorms. It's the human capacity for laziness that drives us to make short term sacrifices (inventing science was no easy feat) for long term pay offs (computers for everyone!).

Thus, I found myself writing an adventure while wedged into seat 24D with a pencil box, a notebook, and two Forgotten Realms sourcebooks (the new 4e one and the DM's book from the old gray box). I had put my D&D books into my luggage because, frankly, I didn't want to carry them around.

The monsters were pretty easy to generate for the adventure - I either remembered their levels, or I built them from scratch (the formulas are easy peasy to memorize, and again my commitment to laziness pays off - I don't need to carry the DMG).

However, I was a little annoyed when working on traps, terrain features, and just general stuff that needed DCs. I couldn't remember the DC progression. I puzzled over it for a few minutes, then realized that my laziness had saved me once again. In an insight so obvious that I feel like punching myself, here's Dr. Mearls' Patented, Super Easy, Instant DC Generator:

1. Start with 10.
2. Add half the trap, encounter, or challenge's level.
3. Do you want only people trained in the skill to have a shot at success? If so, add 5.
4. Think of the stat a PC would need to have a 55% chance of success, assuming the PC is trained if you want only trained guys to have a chance of success. Add that stat's modifier.

Voila! Instant DC.

Here's an example:
In a dungeon aimed at 6th level PCs, there's a locked door. It's a really good lock, so only a rogue or someone trained in Thievery has a chance to open it, but someone who is trained doesn't need much natural talent to open it.

So:
10
+ 3 (half of level 6)
+ 5 (assume training)
+ 1 (a Dex 13 character who is trained should be able to handle this one)

Is a total DC of 19. Voila! An untrained character with a good Dex still has a 30% chance to open the lock.

If you know the PCs' stats, you can achieve a fine control of the DC by using the process above, plugging in the PC's stat mod, then adding 1 to the DC for every 5% you want to drop the success chance.

The nice thing about this method is that it pushes you to think of what the PCs can do, and it's simple enough (IMO) that you can use it on the fly.

OK, back to taking care of all the chores that have piled up since I've been away. I'll talk about GenCon later this week.

22 comments:

edmillionaire said...

*sniff sniff* So intuitive it makes me cry. Plane trips should be a required part of the tail end of your development process.

cyberpunk2020 said...

Anyway, I kind of feel cheated. The better my PC becomes, the higher the DC of a Dungeon Door gets.

Geek Gazette said...

good post. I will have to use your idea.

Mike Mearls said...

Cyberpunk - Only if that's what you, as DM, want to do. In my example, consider the lock to be a level 6 lock. A better lock would be level 8, and so forth. The idea isn't that the lock becomes tougher as you become better - the lock is tougher because you are taking on a more challenging situation.

Level is a function of the challenge level posed by an environment, not the PCs' skills.

ChattyDM said...

Plus, why should doors still pose a challenge after a few levels?

You probably feel cheated because you are analyzing it outside of a game itself where you forget numbers because of the Rules of Cool and Fun.

I crunched the numbers and PC competence advances faster than DCs if you go by page 42. Mikes trick is great for plane ride authors who must have a game ready when they land...

Speaking of which Mike, I created the Adventure Project Kobold Love on my plane ride and it will be featured on my side of the Blogsphere over many weeks.

Having talked to you for some time, I think you will love it.

anonynos said...

@cyberpunk2020

And really, your specific comment isn't something new anyways. As you go up in level the monsters get harder, the traps more deadly, and the doors stronger... because when they don't it becomes trivial. Which, yes, there are times to use trivial encounters but for the most part, trivial= wasted time rolling dice and to me is better as narrative.

DNAphil said...

You had a similar algorithm for the DC's for Zones in the Mastering Iron Heroes book.

I took those algorithms to heart, and have been using them for my IH game for the past three years.

I love these kinds of tips.

ghkj said...

Youth is warcraft leveling not a time of life;warcraft leveling it is a wow lvl state of mind; wow power level it is not power leveling amatter of World of warcraft Power Leveling rosy cheeks, red wrath of the lich king power leveling lips and supple knees;WOTLK Power Leveling it is a matter of thewill,wlk Power Leveling a quality of buy aoc gold the imagination,aoc gold a vigor of the emotions; it is thefreshness of the deep springs wow gold of life. Youth means a tempera-mental maplestory mesos predominance of courage over timidity, of the appetite formaple story mesos adventure over the love of ease. wow gold This often existsin a man of 60 more than a boy of 20. Nobody grows old merely by anumber of years.

xxmy said...

Weekends to peopleig2tmean that they can have a two-day wowgold4europe good rest. For example, people gameusdcan go out to enjoy themselves or get meinwowgoldtogether with relatives and friends to talk with each storeingameother or watch interesting video tapes with the speebiewhole family.
Everyone spends agamegoldweekends in his ownmmoflyway. Within two days,some people can relax themselves by listening to music, reading novels,or watchingogeworld films. Others perhaps are more active by playing basketball,wimming ormmorpgvipdancing. Different people have different gamesavorrelaxations.
I often spend weekends withoggsalemy family or my friends. Sometimes my parents take me on a visit to their old friends. Sometimesgamersell I go to the library to study or borrow some books tommovirtexgain much knowledge. I also go to see various exhibition to broadenrpg tradermy vision. An excursion to seashore or mountain resorts is my favorite way of spending weekends. Weekends are always enjoyable for me.
igxe swagvaultoforu wowgold-usaignmax wowgoldlivebrogame thsaleGoldRockUbrogameswagvaultgoldsoonoforuigxethsale

xxmy said...

Weekends to peopleig2tmean that they can have a two-day wowgold4europe good rest. For example, people gameusdcan go out to enjoy themselves or get meinwowgoldtogether with relatives and friends to talk with each storeingameother or watch interesting video tapes with the speebiewhole family.
Everyone spends agamegoldweekends in his ownmmoflyway. Within two days,some people can relax themselves by listening to music, reading novels,or watchingogeworld films. Others perhaps are more active by playing basketball,wimming ormmorpgvipdancing. Different people have different gamesavorrelaxations.
I often spend weekends withoggsalemy family or my friends. Sometimes my parents take me on a visit to their old friends. Sometimesgamersell I go to the library to study or borrow some books tommovirtexgain much knowledge. I also go to see various exhibition to broadenrpg tradermy vision. An excursion to seashore or mountain resorts is my favorite way of spending weekends. Weekends are always enjoyable for me.
igxe swagvaultoforu wowgold-usaignmax wowgoldlivebrogame thsaleGoldRockUbrogameswagvaultgoldsoonoforuigxethsale

dreaz said...

I am grateful to you for this great content.aöf thanks radyo dinle cool hikaye very nice ssk only cinsellik very nice ehliyet only home free kadın last go korku jomax med olsaoy hikaye lesto go müzik dinle free only film izle love aşk only mp3 indir only radyolar lest go açıköğretim free net only filmler

dfous said...

Bon marche de Dofus Kamas.achat de dofus.le prix moins cher.nous vendons dofus,or de Wakfu. 24/7 appui-en-ligne et livraison rapide.Wakfu Kamas
china: chinaserving

wuyuezhilian said...

I like your blog, it's very good!
By the way, do you like spyder down jackets, I think they are very fashionable and chic, especially the spyder ski jackets, I love them so much. In my spare time, I also like playing tennis rackets, it can keep healthy, what do you like to do?
kids north face jackets
polo vest
polo jacket
abercrombie fitch mens shirts
polo jackets for men
polo jackets for women
burberry shirts for men
polo hoodies for women
columbia jackets women
polo sweatshirts for women
north face jackets on sale
polo shirts for women
polo shirts wholesale
spyder jackets
ralph lauren polo shirt
polo pants for men
abercrombie fitch shirt
wholesale abercrombie fitch shirts
polo vests
polo jackets
polo hoodies for men
burberry shirts for women
burberry shirts on sale
polo shirts for men
north face jackets cheap
north face jackets for women
north face jackets for men
polo sweatshirts for men
columbia jackets for men
columbia jackets discount
spyder jackets for men
discount spyder jackets
cheap spyder jackets
spyder jacket
spyder jackets for women
tennis rackets
cheap tennis rackets
discount tennis rackets
tennis rackets on sale
prince tennis racquets
head tennis racquets
wilson tennis racquets
babolat tennis racquets

lady said...

I like the side of the article, and very like your blog, to write well and hope to continue their efforts, we can see more of your articles. ed hardy clothes. After reading this article has strong feelings, the future will be ed hardy womens longsleeve.ed hardy longsleeve
ed hardy hoodies
ed hardy jeans
ed hardy
ed hardy clothing
ed hardy t-shirts
cheap ed hardy clothing
ed-hardy.co.uk
ed hardy shirts
wholesale ed hardy clothing
ed hardy outerwear
ed hardy mens outerwear
ed hardy womens outerwear
ed hardy clothes
ed hardy boots
ed hardy outerwear
ed hardy hoodies
ed hardy Jeans
ed hardy hoodies
ed hardy jackets
ed hardy womens jackets
ed hardy mens jackets
ed hardy bags
ed hardy trousers
ed hardy shoes
ed hardy longsleeve
ed hardy mens longsleeve
ed hardy womens longsleeve
ed hardy jackets
ed hardy suits
ed hardy clothing
ed hardy shoes
ed hardy jeans
ed hardy boots
ed hardy mens sweater
ed hardy womens cotton
ed hardy womens boots
ed hardy
ed hardy womens clothing

pbsl said...

you have a nice site. thanks for sharing this site. you can download lots of ebooks from here

http://feboook.blogspot.com

nike said...

Nike shoes
puma shoes
Cheap nike shoes
NIKE’s headquartered in Beaverton, Oregon.Nike may be one of the youngest of the major brands, but it is the dominant brand around the world.In 1963-1964 when University of Portland track coach, Bill Bowerman, and Phil Knight, a mid-distance runner joined forces to import and provide low-cost, high tech running shoes from Japan in order to provide alternatives to the German-dominated athletic shoe market.
Discount nike shoes
Wholesale nike shoes
Nike shox r4
Operating under the name Blue Ribbon Sports, Bowerman and Knight began to sell the Japanese Onitsuke Tiger (Nike SB) running shoes. Jeff Johnson, a former rival of Knight, joins the company in 1965 as their first full-time salesperson and sells shoes from the back of his van at local and regional track meets until opening Blue Ribbon Sports’ first retail outlet at 3107 Pico Blvd, Santa Monica California.
nike shox shoes
nike air max
nike running shoes
The Superstar is one of the first designs the Adidas manufactured.The tongue is leather on the outside and cloth of the inside and is thick enough to feel padded, but thin enough to not feel like an obstruction. The heel of the shoe holds up well the curve of the front is great for any kind of feet.
cheap puma shoes
discount puma shoes
nike air max tn
Therefore, Adidas is a collection of trust and respect. Product and marketing initiatives at Adidas primarily focus on five global priorities: football, running, training, basketball and Adidas Originals sneakers. Adidas sports the recognizable logo of three slanted parallel bars of ascending height.
puma mens shoes
puma running shoes
wholesale puma shoes
Everybody like beauty, which is quite commen, especailly womens. Welcom to our store which is focused on sellingghd hair straighteners mk4and hair straightners. For women, especially the young girls, this ghd iv styler hair straightener is the best choice. ghd hair straightners is famouse for the pretty outlook and the top quality. The price of this cheap ghd hair straighteners is acceptable and rational. Ed Hardy Jeans, Ed Hardy Hoodies ed hardy shirts ed hardy clothes ed hardy clothing
ed hardy trousers

liuhua said...

After read your blog, I think you are a wonderful person, for your blog is the best one I have ever seen. If you do not mind, I would like to know do you like fashion? Have you ever heard of polo shirts, which are very chic, especially the polo t shirts, I love them very much. I also like playing tennis rackets, it can keep healthy, what do you like to do? I consider it as my great pleasure to introduce myself as the outlet of polo t shirts women
polo t shirts on sale
and the warmly welcomed
polo t shirts for women
Now. I'd like to introduce our masterpieces, such as
polo shirts on sale
polo shirts men
men's polo shirt
men polo shirt
mens polo shirts
mens polo shirt
besides we also sell
cheap polo shirts
discount polo shirts
men's polo shirts
women's polo shirts
Which are popular with fashinable people. We are also the outlet of
cheap tennis racket
discount tennis racket
in this sporty season, we recommend
prince tennis racquet
head tennis rackets
wilson tennis racket
babolat tennis racquet
There more new products in our store online, we are expecting you to come. We can say that you must find your satisfied things in our store.

virstock.com said...

Dofus Kamas|Prix Moins Cher Dofus Kamas|Kamas par allopass|Dofus kamas audiotel|Dofus kamas par telephone sur Virstock.com

Meilleur prix dofus kamas stock de dofus kamas

Prix moins cher dofus kamas
vente dofus kamas sur www.virstock.com

Kamas par allopass sur dofus kamas

Dofus kamas par telephone sur dofus kamas

Dofus kamas audiotel sur dofus kamas

http://www.virstock.com/jsp/comments.jsp dofus kamas vente

http://www.virstock.com

King Bayern Munich said...

This is a great article, supplies the useful information for me, thanks in this
soft sofa
Modern-stone-sculpture
billiards
Long span shelving
baby stroller
oil paintings
outdoor ceramic tiles
casual shoes
oil paintings

Kelsi said...

christian louboutin shoeschristian louboutin shoes
christian louboutin bootschristian louboutin boots
christian louboutin sandalschristian louboutin sandals
christian louboutin slingbackchristian louboutin slingback
christian louboutin sneakerschristian louboutin sneakers
christian louboutin wedgeschristian louboutin wedges
christian louboutin weddingchristian louboutin wedding
timberland bootstimberland boots
asics shoesasics shoes
asics running shoesasics running shoes
dsquared jeans mendsquared jeans men
dsquared shoes 2011dsquared shoes 2011
karen millen dresseskaren millen dresses

abercrombiefitch said...

the iconic sneaker was originally introduced on now.
Nike Air Max 2011
Nike Air Max Shoes
Nike Air Max
Nike Air Max Wildwood Supreme
Nike Air Max Turbulence
Nike Air Max Skyline
Nike Air Max Goadome
Nike Air Max Fitsole
Nike Air Max Zenyth
Nike Air Max Boots
Nike Air Max Zoom Kobe
Nike Air Max Tn
Nike Air Max LTD
Nike Air Max Presto
Nike Air Max BW
Nike Air Max 24 7
Nike Air Max 2010
Nike Air Max 2011
Nike Air Max 2009
Nike Air Max 95
Nike Air Max 91
Nike Air Max 87
Nike Air Max 180
Nike Air Max Griffey Max 1
Nike Air Max 90
Nike Air Max 1
Abercrombie and Fitch London
Abercrombie & Fitch Clothes
Vibram Shoes
Cheap Air Max
Nike Air Max Shoes
is available in a vivid array of colors, including, Jiffy Black, Pigeon Grey, Shell White, Dodger Blue, and Beaver Brown.

sping.chen said...

Glad to see all the speakers, really wonderful content. Do not know if you like Nike mercurial soccer cleats or Nike soccer cleats and Nike Football Cleats,Nike Mercurial Vapor Superfly with New nike soccer shoes.