So im homebrewing a system and i just want to know the benefits

>>53836664

This is a thinly viewed D100 vs D20 system thread, isn't it.

>>53836664
Rolling under means you have to do less maths, to begin with.

>>53836727
I was thinking in terms of dice pools. The dicepools are very small and use D10s for now (between 2- 5) . But that can easily change.

>>53836779
Speed seems to be the biggest difference.

>>53836664
Rolling under means that players will always know what their chances of success are but it also makes it more difficult to compare threat levels against since everyone is most likely going to be rolling against their highest chance of success unless you force it.

Rolling over is good because you can obfuscate exactly how strong an enemy is while having a clear sort of baseline to compare against but the issue comes from the fact that after a certain point, the numbers will become so large that either you're always fighting an even fight or you're walking into a slaughter.

This is purely anecdotal, but over the years playing both various iteration of d20 as well as CoC and GURPS, I find roll-under to be more intuitive.

As a GM, all you have to handle are modifiers to effective skill; more difficult tasks give a penalty to your TN and easier tasks give a bonus. I find this easier to juggle than d20's system where you have task difficulty as one variable (as DC) and environmental factors as another (skill modifiers). For example, if someone is climbing a wall in a dice+mods system, I have to establish the DC for the wall and whatever situational modifiers apply to the roll itself (rain, exhaustion, encumbrance, etc.), and there's an unnecessary gray area (e.g. is a greased wall a higher DC or a penalty to the roll?). A roll-under system rolls everything into a skill penalty; a difficult climb is a difficult climb, regardless of whether its the wall or the weather or you making it difficult, so slap on a -6 and keep it going. At the end of the day, there's (usually) no difference between upping the DC and penalizing the roll, so why pretend that there is?

As a player, roll-under made understanding my chances of success easier to visualize. If the GM says I'm at an extra -3 to climb that slippery wall in a roll-under system, I add that to my effective skill level with all my gear and training and personal conditions and whathaveyou already factored in and can check with a glance what my odds are. In dice+mods, I've found that GMs are for some reason a lot less comfortable giving out the exact DC (myself included, though again I don't know why), leaving players in the dark unnecessarily.

>>53837330
>In dice+mods, I've found that GMs are for some reason a lot less comfortable giving out the exact DC (myself included, though again I don't know why), leaving players in the dark unnecessarily.
Alot of DM's have trouble accepting player autonomy in the sense that a dude can easily tell the difference between a flat plane of land with no obstacles and walking through a jagged cliffside where landmines are strewn about.

That, and some will also hide the DC's because they want to fudge the DC in a player's favor just in case the players end up failing or some shit.

>>53836664
Roll under can make things a bit quicker to resolve, since both the roll and the target number are accessible to the same person. Contrast roll-over, where you need the GM to tell the player the target, or the player to tell the GM his roll.

However, this advantage only holds when situational modifiers are relatively uncommon. If you're constantly needing to have the GM tell you what modifier to apply to your stat/roll, you're not much better off than in a roll-over system. Roll-over is actually better if various modifiers are fairly ubiquitous, since the application if those modifiers goes a bit more intuitively in roll-over.

The other advantage of roll-under is that if you use a single die roll (eg, d20 or d100, as opposed to something like 3d6 that gives a bell curve), your stat itself shows your chance of success for a "typical" check.

>>53837548
>>53837330

Wouldn't a roll over system be a bit more random though?

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261KB, 300x230px

>>53837483
>tfw my players wanted me to roll in the open
>tfw they thought I was fudging to make the rolls better
>tfw tpk because my rolls were good and they were dumb

>>53836664
Roll-under is inherently finite, as you have a set range of values achievable, barring margins of success/failure/victory, e.g. 1-100 on d100, 3-18 on 3d6, etc., while roll-over isn't without careful planning around modifiers available (bonded accuracy). For example, what might be DC 40 in D&D, which is twice the max of what a d20 can even roll, would be a major penalty to skill/ability in a roll-under system.

Roll-under also shifts the burden of determining success off of the GM and onto the player, as now you only have to worry about situational modifiers instead of sitmods + DC.