Size & Strength DCs

Can giants open their own doors?

Doors in the frost giant stronghold Grimskalle require a DC 20 Strength (Athletics) check to open. Icewind Dale: Rime of the Frostmaiden gives us guidance on the keep’s construction:

How easy is that for a frost giant to open? They have 23 Strength (+6). They also have proficiency in Athletics, which brings their total bonus to +9.

A creature rolling a d20+9 vs. a DC 20 will succeed 50% of the time.

Do frost giants fail to open their own doors 50% of the time?

No.

That’s silly.

Why Can Giants Open Doors?

In abstract, The system works because your push/carry/lift capacity doubles each time you double your size.

So, a huge giant has a push capacity of 120x their Strength score. That’s 2,760 pounds for a frost giant.

Checking back in with our doors, they don’t provide a weight. But, we know it’s 500 ft³ of ice based on the size description. At 57.2 lbs/ft³ for ice, that door is 28,600 lbs. That’s way too much to push, even for frosty. But, a door is not just a block in the way. It’s hinged.

At this point, we need an engineer, because I have no idea how much a hinge can reduce the force required to move a door. An engineering consult is a good barometer to tell you’ve gone too far to satisfy a fictive narrative.

Lessons

What lessons can we learn having come this far?

While Strength and size modulates push/lift/drag weight, it doesn’t translate neatly to a roll vs. a DC.

How does size impact Strength checks? Certain mechanics in the game (such as the Enlarge spell) rely on the advantage mechanic to increase a player’s likelihood of success.

The problem with advantage mechanics is that while they make the results you can already hit more likely, they do nothing to raise the top end of capability for a character. Note: If you’re curious in seeing how this kind of difference shakes out, check out the War Caster vs. Resilient (CON) article.

So, if you couldn’t open a big door before, being bigger won’t help you at all. That seems like it’s missing something. Being bigger should expand the top range of your Strength capabilities.

So, how do we patch that directly into the DC?

The Fix

Including the actual push weight of a door seems too mechanical, but it would draw a bright line for when you’re strong enough to skip the check. The problem is, this fix still exists outside the world of the skill check. It doesn’t help the check make sense when you need to actually roll it.

Here’s some ideas for building the mechanics into the roll:

DC Adjustment

Well, just as the carry/push/pull/drag weight doubles for each size increase, perhaps Strength DCs should halve for each size category.

Since this is likely to quickly trivialize Strength checks for larger creatures, a more appropriate suggestion might be slicing the DC by 5 for each size category. This latter suggestion is a neat fix in our Grimskalle example, since it means frost giants will never have trouble opening a DC 20 door.

Size Benchmark

If you’re a designer, perhaps you should include a size benchmark right in the text. For example, “creatures smaller than Huge must make a DC 20 Strength (Athletics) check to open the door.”

This implementation is clean, but also super messy.

It’s clean because it’s right there in the text. You don’t need to patch anything in the base game. New players don’t need to know weird size rules. It gives you freedom to add it or not.

It’s messy because the designers need to remember to add it every time. And repetition takes space in books that need page count to deliver content.

Consider the freedom this case-by-case implementation gives you. After all, perhaps not every door should be easier for big things to open. Maybe it’s a really small door that’s barricaded, and the large creature would have a tough time getting leverage in the space.

Thanks to Ben Potts (@BenPotts on twitter) for this suggestion.

Collective Strength

Borrowing some legacy design from Tales from the Yawning Portal conversions, we can set a combined Strength score to move the door. For example, “medium creatures with a combined Strength score of 40 can open the door.”

This is a fun technique because it gets the players working together. If they don’t have the combined Strength to open the door, they also have other creative options beyond rolling vs the DC. They can augment their Strength scores with spells and consumable items. Just make sure to seed those potions a little earlier in the adventure.

Thanks to Zipperon Disney (@ZipperonDisney on twitter) for this suggestion.

I hope you enjoyed this design analysis! It’s all made possible by our supporters on the ThinkDM Patreon.

4 thoughts on “Size & Strength DCs

  1. I would suggest that the giants are able to open their own doors because there is no meaningful impact to failure, thereby no need to roll dice. Reviewing the rules about Ability Checks, one discovers.

    “An ability check tests a character’s or monster’s innate talent and training in an effort to overcome a challenge. The DM calls for an ability check when a character or monster attempts an action (other than an attack) that has a chance of failure. When the outcome is uncertain, the dice determine the results.”

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    1. Maybe not when it’s just giants lounging around, having a good time with thier buddies, but I would argue that once a bunch of murderrats or other much smaller than you but still trying to and capable of killing you creatures broke into YOUR house you would have a much less blasé attitude towards the meaningful impact of failing to open a door.

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      1. You are still assuming that the giants have a chance at failure. The rules say when there isn’t a chance of failure you don’t need the dice.

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