Tabletop System Conversion

The Viridian TTRPG game system is based on a d100 key die and contains mechanics and rulings that differ from some other TTRPG systems. However, it should be noted that parts of Dungeons and Dragons 3.5 and Pathfinder 1 can be converted for use in the Viridian system following these guidelines. For clarity, Pathfinder is going to be the system focused primarily during this guide, due to it being the most up to date of the 3.5e-style d20 systems.

Convertable Mechanics (3.5/PF)

d20 to d100

Viridian uses a d100 as it's key die, for effects that are normally governed by a d20, simply multiply the result of a d20 by 5 to get the result for a d100.

ex. A player rolls a 6 on their d20 in a game of Pathfinder. In Viridian, this would count as a 30 on their d100.

Weapon/Attack Damage

The damage from attacks and weapons from DnD 3.5 and/or Pathfinder can be converted to Viridian TTRPG standards by observing the damage die of the attack (for a Medium creature) and applying them into two properties. Direct-Damage value and Damage-Spread value.

Weapon/attacks in Viridian have Direct-Damage to ensure such actions deal reliable damage on hit after passing an Accuracy/ToHit check. Damage can often be reduced due to Damage-Reduction found in armour worn by Adventurers and other effects, including special defensive actions.

Viridian uses higher damage values than other games, which is reflective of the Damage-Spread property, keeping an air of tradition by keeping random damage values, but as an addition to the direct damage, not the primary source. Certain conditions may allow an Adventurer or creature to deal maximum damage with their Spread, whereas other conditions may negate Direct-Damage and only allow Damage-Spread to be deal instead.

When a Weapon/Attack gains more dice (1d8 to 2d8), only Direct Damage is increased (16 + d8). But when a Weapon/Attack changes the kind of die used (1d8 to 1d12), both Direct Damage and Damage-Spread must be updated (12 + d12).

ex. A Longsword, with a damage die of 1d8, will have 8 Direct-damage and d8 Damage-Spread.

Attack damage always starts by treating the original damage die as dealing maximum damage for the die depicted. Longswords have a d8, therefore Direct damage is 8.

Additional damage in the form of Damage-Spread uses the same die as the weapon/attack used originally. Longswords will deal an additional d8 (1-8) damage on hit.

Therefore, a Longsword from DnD/Pathfinder will deal 9-16 damage on hit under normal circumstances.

Armour and Shields

Armour and Shields in Viridian do not have Armor-Class (AC). Even though there is a comparable mechanic called Defence, Armor and Shields instead grant the wearer/wielder Damage-Reduction instead. Whatever AC bonus a piece of Armour or Shield would give, it will reduce an incoming attack's damage by that amount instead.

Armor-Check Penalty uses d100 for any relevant skills, multiply the value by 5 to get the effective Skill rating while the armour is worn. Speed reduction due to heavy armour is instead calculated through the Load-Point system. You can choose to assume any Medium and Heavy armour is treated as being a 'Light-Load' at all times, or treat the Armour's weight in LBS being equal to the amount of Load-Points wearing that armour is considered to be.

Maximum Dex bonus and Arcane Spell Failure Chance are not mechanics supported in Viridian, therefore these properties can be stripped/ignored in conversion.

Speed/Movement/Distance

No special adjustments are needed for the way that distance and movement is calculated between Viridian and DnD/Pathfinder.

Both games employ the use of Square-grid layouts that are measured roughly 5ft in width and depth and the base speed for Medium and Small-sized characters are 1:1 reflective of those used in Viridian. Humans move 30ft or 6 squares per round and most Small races (and Dwarves) move 20ft or 4 squares.

However, be mindful that the Size mechanics of Viridian supersede the effects of any abilities, spells or effects that change size. Specifically, ones such a Enlarge/Reduce Person will use Size-Rating properties, which itself affects creatures differently to what the spell does originally.

Size Categories

Both Dungeons and Dragons and Pathfinder had 9 Size categories for creatures and gameplay-relevant objects:
Fine, Diminutive, Tiny, Small, Medium, Large, Huge, Gargantuan and Colossal.

The following categories from other systems have Size-ratings of:
Fine:        0.1
Diminutive:  0.2
Tiny:        0.4
Small:       0.7
Medium:      1
Large:       2
Huge:        4
Gargantuan:  8
Colossal:    16

See the Size article for more information about what properties are affected when converting Non-Medium sized creatures to Viridian.

Class-Based Conversions

Because Viridian is a classless/open-progress style of RPG, the more ridged aspects of Class-based levelling does not apply here. However you can still use features and abilities of classes provided they are supported by this game's Skill system.

Class feature availability

Due to the way that Skill-caps work and Skill ranks in general. The available class features for a converted character class is as follows:

* Each Skill Rank in a 'Class Skill', is equal to 4 levels in a Pre-conversion system.
  ex. If you have one (1) rank in a Fighter-based Skill, then you are treated as if you were Lv4 for the purposes of what features a Fighter class gives in another system.
  ex. If you had 3 ranks in a Wizard-based Skill, then you would instead be given access to any features and spells that a Lv12 would be allowed to have in another system.

Before Lv4 (in Viridian), characters cannot exceed 40 Skill-Rating or 2 Skill ranks in any skill, therefore a converted character could be considered to be a Lv8 class pre-conversion, they cannot exceed this limitation until they reach Lv4 in Viridian TTRPG, at the very least.

Spell Levels

Many classes in other systems need the character to be a certain level before they could be permitted to cast them. Such as Wizards, Sorcerers, Druids, Paladins, Rangers, Clerics and Psions.

Assume that each of the 5 Skill ranks representing a class unlocks 2 spell levels each:

Rank 1: 0th and 1st level
Rank 2: 2nd and 3rd level
Rank 3: 4th and 5th level
Rank 4: 6th and 7th level
Rank 5: 8th and 9th level