I don’t know if the question is appropriate to the forum—sorry if it isn't—but has anyone done a dependable conversion of d20 to d6, and vice versa? There are a lot of things from the wider OGLU that would be handy to have at hand while running Traveller; and I am thinking here mostly of adaptable critters....
CT/MgT <-> D20
- Thread starter Lemnoc
- Start date
mechascorpio
Mongoose
There was actually some discussion and advice on that here on this forum quite a number of years ago.
mechascorpio said:
That's interesting, and the 1.5X characteristics multiplier is fairly obvious/intuitive. Unfortunately, T20 Lite does not seem to be available anywhere. And I am at this moment most interested in quick SIZE/HP conversions/guidelines, so that a "Giant Spider" translates across nicely to a "Giant Space Spider" ...for example.
ShawnDriscoll
Cosmic Mongoose
The D20 system isn't that popular in sci-fi RPGs. Classes/races are bit restrictive for what players want to achieve with their characters.
ShawnDriscoll
Cosmic Mongoose
Are your players ok with generating older characters and starting a game already leveled up? Or do they all want to be age 18 and level up as they play? And will your NPCs be leveling up as well to match the levels of the PCs?
Nathan Brazil
Banded Mongoose
I have been working on a general one for d20SRD for a while now, but I am not at a point to really publish it. However for those interested in making one of there own system, perhaps they can make use with these barebone assumptions.
0.The idea is to get things to convert back and forth. Most people either want a precise mathematical conversion of odds due to the 2d6 bell curve vs 1d20 linear odds, at the other end a story 'feels right' and you just make it up case by case. I chose to go with third path which ignores the odds but is much more systematic than you would think.
1.Decide on your ruleset. I chose Mongoose Traveller as it is the latest system and its supplements have displayed the flexibility by examples.
2.The core mechanic of activities in both games is the Task Roll or the D20 DC roll (duh...). Both games use a descriptive name (Easy, Average, Formidable, Heroic, Nearly Impossible) to describe storywise the level of difficulty of the task involved. of difficulty (+/-2 for Traveller, +/-5 for Traveller). I created a conversion chart with the following:
0.The idea is to get things to convert back and forth. Most people either want a precise mathematical conversion of odds due to the 2d6 bell curve vs 1d20 linear odds, at the other end a story 'feels right' and you just make it up case by case. I chose to go with third path which ignores the odds but is much more systematic than you would think.
1.Decide on your ruleset. I chose Mongoose Traveller as it is the latest system and its supplements have displayed the flexibility by examples.
2.The core mechanic of activities in both games is the Task Roll or the D20 DC roll (duh...). Both games use a descriptive name (Easy, Average, Formidable, Heroic, Nearly Impossible) to describe storywise the level of difficulty of the task involved. of difficulty (+/-2 for Traveller, +/-5 for Traveller). I created a conversion chart with the following:
Code:
D20 Task DC Traveller Check
? -5 Simple +6
Very Easy 0 Easy +4
Easy 5 Routine +2
Average 10 Average +0
Tough 15 Difficult -2
Challenging 20 Very Difficult -4
Formidable 25 Formidible -6
Heroic 30 ? -8
Superheroic 35 ? -10
Nearly Impossible 40 ? -12Nathan Brazil
Banded Mongoose
3.Because of this, it seems that each +5/-5 from the DC relates to a +2/-2 in Traveller Which means that you can convert bonuses back and forth:
D20 to Traveller
DC DM
+1 +0
+2 +1
+3 +1
+4 +2
+5 +2
+6 +2
+7 +3
+8 +3
+9 +4
+10 +4
D20 to Traveller
DC DM
+1 +0
+2 +1
+3 +1
+4 +2
+5 +2
+6 +2
+7 +3
+8 +3
+9 +4
+10 +4
Nathan Brazil
Banded Mongoose
4.Now for your d20 character's or monster's or animal's stats
Take the d20 stat and divide by 1.5 This means that the D20 "human range" of stats from 1 to 23 can resolve to the Traveller "human range" of stats from 1 to 15.
A.The Charisma Stat - Mongoose already shows in the Core Rules that stats can be created. Charisma, Caste, and so on. The Judge Dredd supplement uses a stat called Influence in addition to Social Standing. The Influence stat more closely correlates to the D20 version of Charisma. So why not a 7th stat? Or 8th since Psionic Strength is already a de facto 7th stat for many games.
B.The Social Standing Stat - I do not have strong rules here other than creating a chart. My Fantasy Traveller chart draws on the concepts from Book 8: Dilletante about range of Social Standing. It includes D20 Deity Ranks for multiversal planes, so that shows you how nutty I can be.
C.Intelligence, Wisdom (D20) vs Intelligence, Education (Traveller) and Instinct
Decide if your creature/race/whatnot is sentient or not.
If it an animal like (D20 Intelligence of 1 or 2), the it is an animal, D20 Intelligence = Intelligence, D20 Wisdom = Instinct
If not, I swap stats so D20 Intelligence = Traveller Education, D20 Wisdom = Intelligence. Or not if you don't like it.
Don't forget to divide by 1.5...
Take the d20 stat and divide by 1.5 This means that the D20 "human range" of stats from 1 to 23 can resolve to the Traveller "human range" of stats from 1 to 15.
A.The Charisma Stat - Mongoose already shows in the Core Rules that stats can be created. Charisma, Caste, and so on. The Judge Dredd supplement uses a stat called Influence in addition to Social Standing. The Influence stat more closely correlates to the D20 version of Charisma. So why not a 7th stat? Or 8th since Psionic Strength is already a de facto 7th stat for many games.
B.The Social Standing Stat - I do not have strong rules here other than creating a chart. My Fantasy Traveller chart draws on the concepts from Book 8: Dilletante about range of Social Standing. It includes D20 Deity Ranks for multiversal planes, so that shows you how nutty I can be.
C.Intelligence, Wisdom (D20) vs Intelligence, Education (Traveller) and Instinct
Decide if your creature/race/whatnot is sentient or not.
If it an animal like (D20 Intelligence of 1 or 2), the it is an animal, D20 Intelligence = Intelligence, D20 Wisdom = Instinct
If not, I swap stats so D20 Intelligence = Traveller Education, D20 Wisdom = Intelligence. Or not if you don't like it.
Don't forget to divide by 1.5...
Nathan Brazil
Banded Mongoose
5.Skills: Create a mapping chart to relate the D20 Skills with the Traveller Skills. Some are really easy to match others are not. D20 Modern SRD skill list differs from D20 SRD so keep that in mind. Base Attack and Magic Caster Level are separate skills addressed later.
Drawing on the previous chart of DC to DM is a simple matter. In d20 some skills cannot be attempted if there are no skill ranks, others receive a non-proficiency penalty, others there is no issue. Does not matter. You are using skills of the ruleset you converting to. Adjust up or down as desired
Ranks Level
1 0
2 1
3 1
4 2
5 2
6 2
7 3
8 3
9 4
10 4
11 4
12 5
13 5
14 6
15 6
16 6
17 7
18 7
19 8
20 8
Drawing on the previous chart of DC to DM is a simple matter. In d20 some skills cannot be attempted if there are no skill ranks, others receive a non-proficiency penalty, others there is no issue. Does not matter. You are using skills of the ruleset you converting to. Adjust up or down as desired
Ranks Level
1 0
2 1
3 1
4 2
5 2
6 2
7 3
8 3
9 4
10 4
11 4
12 5
13 5
14 6
15 6
16 6
17 7
18 7
19 8
20 8
Nathan Brazil
Banded Mongoose
6.Base Attack - This is either Melee Combat or Athletics (Archery or Bows or Thrown Weapon, or etc.). Match each weapon to an appropriate skill (Melee Cbt, Atheletics or Gun Cbt or Heavy Weapons or whatever). To determine the skill, simply take the characters favored weapon. Smack the BAB against the Skill level conversion chart from before.
6.Racial abilities, Extraordinary abilities, Feats and other things - In general....
Take a look at the Mongoose Judge Dredd and Strontium Dog books. They both have capabilities called 'Special Techniques'. You can in different ways get one instead of a Traveller Skill Level. Compare intent of the game mechanics and wording of the special techniques vs. the wording of similar D20 SRD feats and not the actual numbers crunching. So....
Keep special abilities, feats, racial abilities, and so on that cannot be applied to an existing skill. Items which provide bonuses to skills, modify bonuses per my assumption 3, which means that some feats are simply another skill level to an existing skill and anything with only a +1 bonus goes away. Don't worry about pre-requisites (Like Weapon Spec. and Greater Weapon Spec.). A +1 to D20 DC is not significant enough for Traveller to make a difference (as shown back in assumption 3 in my previous post.)
6.Racial abilities, Extraordinary abilities, Feats and other things - In general....
Take a look at the Mongoose Judge Dredd and Strontium Dog books. They both have capabilities called 'Special Techniques'. You can in different ways get one instead of a Traveller Skill Level. Compare intent of the game mechanics and wording of the special techniques vs. the wording of similar D20 SRD feats and not the actual numbers crunching. So....
Keep special abilities, feats, racial abilities, and so on that cannot be applied to an existing skill. Items which provide bonuses to skills, modify bonuses per my assumption 3, which means that some feats are simply another skill level to an existing skill and anything with only a +1 bonus goes away. Don't worry about pre-requisites (Like Weapon Spec. and Greater Weapon Spec.). A +1 to D20 DC is not significant enough for Traveller to make a difference (as shown back in assumption 3 in my previous post.)
GypsyComet
Emperor Mongoose
ShawnDriscoll said:
D20 Modern/Future was a bit too stilted toward the Pulp-y Space Opera side.
T20 suffered from bigbook-itis and some unfortunate organizational choices. It did, however, minimize the effects of classes as straightjackets. You could mix and match widely, if not always freely, as some of the career classes were tied to the prior experience process.
Nathan Brazil
Banded Mongoose
Describing Races: Use or create Alien Traits to describe races. Flynn's Guide to Alien Creation (an "Traveller Compatable Product") by Jason "Flynn" Kemp is I cannot stress more, an excellent guide (Thank you Mr. Kemp!). His bonuses for some Alien Traits do not correlate to my conversion, but I use it as a base.
In converting natural weapons, Supplement 11: Animals Encouners p.25 (example Tramples and Stomps = Thrasher) has a chart which describes many SRD natural attacks into Traveller natural weapons.
Since Traveller does not care about Challenge Ratings or game balance in the normal D20 way, don't worry about it.
Example: Elves
Genetic
• Notable Dexterity (+1), Weak Endurance (–1)
• Acute Hearing (+1 to hearing based Recon tasks)
• Acute Sight (+1 to sight based Recon tasks)
• Low-Light Vision
• Immunity to magic sleep effects, and a +1 DM to Resistance enchantment spells or effects.
• An elf who merely passes within 1.5 meters of a secret or concealed door is entitled to a Very Difficult Recon check (-4) check to notice it as if she were actively looking for it. An elf’s senses are so keen that she practically has a sixth sense about hidden portals.
Social (May take instead of a homeworld or education skill choice)
• Racial Weapons: Longsword, Rapier, Composite Longbow, Composite Shortbow, Longbow, Shortbow (Provides a Melee (name of weapon) 0 with ONLY those weapons, so taking this is not the same as getting Melee Combat (Blade) 0 and Athletics (Bows) 0. Also no way to increase these skill Levels normally).
• Language 0 (to "know" Common trade tongue)
In converting natural weapons, Supplement 11: Animals Encouners p.25 (example Tramples and Stomps = Thrasher) has a chart which describes many SRD natural attacks into Traveller natural weapons.
Since Traveller does not care about Challenge Ratings or game balance in the normal D20 way, don't worry about it.
Example: Elves
Genetic
• Notable Dexterity (+1), Weak Endurance (–1)
• Acute Hearing (+1 to hearing based Recon tasks)
• Acute Sight (+1 to sight based Recon tasks)
• Low-Light Vision
• Immunity to magic sleep effects, and a +1 DM to Resistance enchantment spells or effects.
• An elf who merely passes within 1.5 meters of a secret or concealed door is entitled to a Very Difficult Recon check (-4) check to notice it as if she were actively looking for it. An elf’s senses are so keen that she practically has a sixth sense about hidden portals.
Social (May take instead of a homeworld or education skill choice)
• Racial Weapons: Longsword, Rapier, Composite Longbow, Composite Shortbow, Longbow, Shortbow (Provides a Melee (name of weapon) 0 with ONLY those weapons, so taking this is not the same as getting Melee Combat (Blade) 0 and Athletics (Bows) 0. Also no way to increase these skill Levels normally).
• Language 0 (to "know" Common trade tongue)
Nathan Brazil
Banded Mongoose
I am not good at spacing things out. Sometimes using code monospaces the values.
The question marks represent unknown or unspecified value. Specifically, Traveller and D20 do not have words to describe the represented numeric value. Importantly in the case Traveller, it does not have words in the Core Rules to describe Tasks beyond Formidable (-6). From a number crunchy standpoint it is possible, but not terribly likely, to achieve very high rolls:
12 2d6 Roll
+3 Stat DM Max for unenhanced human
+4 Skill Level 4 (generally described expert, best in the world, etc.)
+1 DM from a tool (if applicable)
+1 Taking Extra time (if applicable)
===
21 = total roll
-13 Task Difficulty
===
8 Still a success
The question marks represent unknown or unspecified value. Specifically, Traveller and D20 do not have words to describe the represented numeric value. Importantly in the case Traveller, it does not have words in the Core Rules to describe Tasks beyond Formidable (-6). From a number crunchy standpoint it is possible, but not terribly likely, to achieve very high rolls:
12 2d6 Roll
+3 Stat DM Max for unenhanced human
+4 Skill Level 4 (generally described expert, best in the world, etc.)
+1 DM from a tool (if applicable)
+1 Taking Extra time (if applicable)
===
21 = total roll
-13 Task Difficulty
===
8 Still a success
Nathan Brazil
Banded Mongoose
Yes, If people like, but this is the Traveller forum. My conversions were designed for generic D20SRD and D20Modern SRD, including magic (*gasp*!). Then again in Traveller, magic systems have already been introduced inLemnoc said:Nathan Brazil, extremely helpful, thanks! More installments? Keep 'em coming!
Strontium Dog
Flynn's Guide to Magic in Traveller
Netherell
Worlds Apart
Nathan Brazil
Banded Mongoose
D20 Armor Class vs. Armor Protection Value:
The D20 SRD describes bonuses of various types. It also treats AC as an all or nothing proposition. Traveller makes the distinction between being hit or not, and when hit that your armor reduces damage. This is actually easy peasy to convert.
Look at the D20 bonuses granted. Decide which ones which just make the target harder to hit and which actually protect you from the sword, bullet, etc.
Remove the DEX bonus for a start. It is accounted for in Traveller combat (duh...)
Next was to look at the touch attack vs general attacks. If it works against the attacker just to touch, it is a + or - DM (don't forget curses the cause minuses ) to the attack roll itself. If not it is probably armor protection value. Divine, profane, deflection, etc.. Sound like things to keep you from getting hit. Equpment, Armor, Natural Armor, Shield. Yea, sounds like armor.
So, they are sorted. What do I do?
DMs to hit or not are treated via the same bonus chart for DC to DM.
Armor Protection
Supplement 4: Central Supply Catalog had some fairly good examples of Archaic Armor which provided protection in the range of 1 to 6 points which more or less matched SRD armor descriptions rated from 1 to 8. So I took SRD Armor x 6 /8 and that provides the Protection Value for Traveller. So your basic Age Category 12 Red Dragon has +39 Natural Armor. That makes for a nasty protection value of 29. Easy to hit, still hard to damage.
The D20 SRD describes bonuses of various types. It also treats AC as an all or nothing proposition. Traveller makes the distinction between being hit or not, and when hit that your armor reduces damage. This is actually easy peasy to convert.
Look at the D20 bonuses granted. Decide which ones which just make the target harder to hit and which actually protect you from the sword, bullet, etc.
Remove the DEX bonus for a start. It is accounted for in Traveller combat (duh...)
Next was to look at the touch attack vs general attacks. If it works against the attacker just to touch, it is a + or - DM (don't forget curses the cause minuses ) to the attack roll itself. If not it is probably armor protection value. Divine, profane, deflection, etc.. Sound like things to keep you from getting hit. Equpment, Armor, Natural Armor, Shield. Yea, sounds like armor.
So, they are sorted. What do I do?
DMs to hit or not are treated via the same bonus chart for DC to DM.
Armor Protection
Supplement 4: Central Supply Catalog had some fairly good examples of Archaic Armor which provided protection in the range of 1 to 6 points which more or less matched SRD armor descriptions rated from 1 to 8. So I took SRD Armor x 6 /8 and that provides the Protection Value for Traveller. So your basic Age Category 12 Red Dragon has +39 Natural Armor. That makes for a nasty protection value of 29. Easy to hit, still hard to damage.
