Hello Everyone and Welcome to Raiders of the Quantum Sea!

Our game is a Star Frontiers campaign using my House Rules system called OneRolld20, which has developed from my take on Heads or Tales, Celestial Mechanics, and Fate.

This thread will post rule conversions, links, and world info.

Core Rules:

OneRolld20
Zebulon's Guide supplement to Advanced Star Frontiers

Classes will be used as starting kits for characters, and they can be developed using the Star Frontiers rules however you want.  The character and their backstory will provide the baseline that we use for determining results of actions with OneRolld20.
This message was last edited by the GM at 18:38, Mon 13 Apr 2020.

It's a really simple concept called "Narrative Roleplaying".

Basically, you describe what your character wants to do in response to a given situation, and I tell you what happens.  Trust me!  :-)

I already know generally how good your character is, how difficult the task they are attempting is, how strong the bad guy is, how useful their tools/weapons/techniques are, and what their opposition (if any) is attempting to do back.

You describe in as best detail as you can (or desire), and mention what things you think would help you that you are using.

Then, you roll a d20.

That's it.  :-)

Even numbers are successes, odds are failures.

How high or low you roll determines how much of a success or failure you had.

A "20" is a maximum (even critical) success, and a "1" is a critical failure.

Everything else is in between.

The GM never rolls- you are in charge of your own fate!  :-)

All I do is weigh the factors involved, and describe what happens.

Keep in mind, some things are so difficult that a maximum success still fails (although you may gain information about what might need to be done to help), and some things are so easy that even a pretty bad failure still succeeds to some degree.  All this is on a case-by-case basis based on the character vs. what they are trying to do, and with what assistance.

Everything is done narratively, so the numbers of your character statistics, ammunition levels, power points in your equipment, injury levels, etc. all are dealt with a little "fuzzily" and don't have to be tracked numerically as much as usual.  (Examples to follow)

The character sheet is just a baseline, and a way to track long term development, like skill levels or equipment, for example.

All of this is much more intuitive than you'd think, after years of playing rpg's, and it allows a lot to be accomplished quite quickly in a world where we don't have much time to game.

One roll could be the results of one "combat round", or the results of a whole battle between space fleets.  Or the results a single delicate surgical procedure, or hacking a computer, or doing a criminal investigation, or...

Generally the results of a roll will be more "fine-grained" the more important/critical the action is, or if it's against a more challenging or important adversary.  (Examples to follow)

In actual play for this setting, these rules should result in a feel very much like some of the best pulp sci fi from the 60s and 70s (like Poul Anderson and Harry Harrison, for example).
This message was last edited by the GM at 18:42, Mon 13 Apr 2020.

I think a few quick combat examples should illustrate all the concepts, as unopposed tasks are very straightforward.

Think of combat in terms of rounds of 2-3 seconds each.  All initiatives are resolved simultaneously for each action, although logic might indicate that some things are faster than others.  When necessary (like some kind of surprise situation), you can roll to see if/when you get to respond.

In that time, everyone gets two actions, they can be move, shoot, draw a weapon or item, reload (one task if already to hand), operate a simple piece of equipment, aim, etc.

Some tasks take the whole round, e.g.- pulling out a magazine and reloading. drawing and readying a grenade, etc.

You can repeat the same action more than once per round.

Moving one step in any direction is free, as is drawing a ready weapon that you have a hand on, etc.  Whatever makes sense.

So, with that in mind:

A Bad Guy draws a weapon and attempts to shoot you.  You draw a weapon, take one free step to cover, and shoot back.

This is easy, assuming no one is surprised.  It takes one action for each person to draw, so you only have to worry about the shooting.
With semi-automatic weapons, you can shoot 1,2, or up to 4 times per action, each action directed at one target.  More shots can do more damage, and increases the likelihood of hitting up close, but decreases it (a lot) further away.  Full auto weapons shoot 3 round burst, two 3 round bursts, or a 12 round "full auto" burst.  Same general idea, but automatic weapons have a better chance to hit in general, and you could spread multiple bursts or a single long burst across multiple targets near each other.

So, you draw and shoot twice this round.  I know how good your skills are, as well as those of the Bad Guy.

You roll a 16.  That's a really good success, and does most of your weapon's damage (maybe 3/4 damage).

I would look at what setting your weapon was on, and rough estimate what that would do to a shield, armor, or the bad guys' stats, and then describe the action and what you see as an effect.

A 20 would hit with max damage.  If you were really good, and they weren't, maybe you might get two bad guys, or have some other effect.

If you took an action to aim, you'd have a better success when you succeed, but it takes at least one action to do that.

Similarly, if they were taking a whole action to dive to really good cover, your previous roll of 16 might only do 1/2 damage, instead of 3/4.

That's it!  :-)

What if you rolled a 19?  That's a minor failure.

You probably just miss (mind your back stop!). :-)

But what if you rolled, say, a 7?  That's a pretty bad failure.

In that case, you probably miss and get shot back.  I would keep in mind what I thought my bad guy was doing, as well as the fact that you stepped to cover, which would mitigate damage some.

And of course, a 1 would be really bad, with maybe your weapon jamming or some such as well...

What if you roll a good success, but I still describe a failure?

Say, you shoot a Sathar robo-monster with a laser rifle on maximum with say, a 20 as a result... and nothing happens?

Then it's most likely that you don't have the capability to hurt it that way, or not that way without doing something else first- like noticing there is a control panel nearby that might turn off it's defenses, or noticing that it has a special force field that doesn't cover it from behind, or some such...

From this, I hope you see that any other combat action can be modeled similarly, and that unopposed actions, like picking a lock or repairing a star ship just require a some appropriate skill, and a decent successful roll.  If you can use a good description to illustrate things you are using or steps you are taking to make the task easier, your results will reflect that.

And that's all there is to it!  :-)
This message was last edited by the GM at 21:30, Mon 13 Apr 2020.

In our game, the various shield (screen) types are reduced to one- the standard "force field".  This one shield type has varying effects on the different weapon types that impact it.  Additionally, armor has varying effectiveness depending on the weapon type that impacts it.  This simplifies, but generally replicates the overlapping intersections of weapon/shield/armor in SF.

Keep in mind that these numbers are not actually used in play, they are just guidelines for understanding how things interact when there is a die roll to resolve combat in OneRolld20.

Here is the table we will use:

Weapon Type       Shield Effect       Armor Effect
Laser                     Full                      Full
Plasma (Rafflur)    1/2                       Full
Electron                 Full                      1/2
Maser                    1/2                       0 (Metal=Full)  (Masers cause 1/2 damage to tissue, double damage to electronics)
Sonic                     0                          1/2 (Sonic weapons cause 1/2 damage to non-living material, double damage to tissue)
Bullet (Gyrojet)     1/2                        Full
Bolt (Ion)               1/2                        1/2
Blade/Bludgeon     1/2                        Full

Shields absorb damage per attack, limited by the table above.  Each point absorbed costs one point of power.  When a shield runs out of power, it goes down.

Examples:

A 20 point laser rifle blast will be absorbed by a shield completely, costing 20 energy points.  Once the shield goes down (even if while absorbing a single blast), the rest of the damage goes through.

A 12 round burst from an assault rifle has 6 rounds hit the shield, for 18 points of damage.  The shield absorbs 9 points of damage, for 9 energy points expended, while 9 points pass through to strike the target.


Armor absorbs a number of points equal to its armor value/10, and limited by the table above.  When armor has absorbed a number of points equal to its armor value, it no longer functions and must be repaired or replaced.

Sample Armor:

Light Skeinsuit (Skeinvest/Civilian concealable armor)- 20 points (absorbs 2 points of damage)
Medium (Standard) Military or Civilian Skeinsuit- 50 points (absorbs 5 points of damage)
Heavy Military Skeinsuit (Think Aliens body armor)- 75 points (absorbs 8 points of damage)

Note:  A robot may be plastic or metal cased.  Metal cased robots will have their armor absorb full value from maser weapons.

Examples:

A standard military skeinsuit is hit with two 10 point laser pistol blasts.  The suit absorbs 5 points of damage from the first hit, passing 5 points through, and takes 5 points off of its 50 points of durability.  The next hit will still absorb 5 points of damage and pass 5 through but durability value of the armor will now drop to 40.

The same skeinsuit is hit with an electron beam for 4 more points.  Since the armor only absorbs half damage from electron weapons, it is not stopped by the armor.  The armor absorbs 2 points of damage, and passes 2 points through.  The armor durability now drops to 38.

The same skeinsuit is then hit with a 4 point blast from a maser rifle (Razer).  All 4 points pass through.  (Note that a person would only take 2 of those points of damage, since masers are more effective on electronics.)

A heavy military skeinsuit (with hard armor) is hit with a 6 point blast from a sonic disruptor.  The armor absorbs 3 points of damage, and passes 3 points through.  Its durability drops to 72.

The same skeinsuit is hit with a 4 point maser rifle (Razer) blast.  4 points of damage is absorbed, and the armor value drops to 68.
This message was last edited by the GM at 18:09, Mon 13 Apr 2020.

These guidelines will be helpful in determining where your character stands when attempting to do things, or resolving combat, etc.

Power packs are rechargeable unless otherwise stated.

Power pack sizes are:

Micro Disk (50 cent piece size)- 10 SEU
Mini (pack of gum size)- 20 SEU
Standard (M16 20 rd. magazine size)- 50 SEU
Large (Double Standard)- 100 SEU

Parabatteries can be used as power packs.

Parabattery sizes are:

Type 0 (fanny pack size)- 250 SEU
Type 1 (small of back day pack size)- 500 SEU
Type 2 (backpack size)- 1000 SEU
Type 3- 2000 SEU
Type 4- 4000 SEU
(additional sizes as appropriate)
This message was last edited by the GM at 21:29, Mon 13 Apr 2020.