Rolling
Randomize item generation using roll numerators for scalable probabilities
What is Rolling?
Rolling is the process of generating randomized items or loot based on their defined properties. In Forge, rolling uses a roll numerator system, which ensures scalable and dynamic probabilities as you add or adjust items or classifications in your game.
How Roll Numerators Work
Each item or classifier option is assigned a roll numerator, representing its weight in the roll. The system calculates the roll denominator as the sum of all numerators for the available options. An item’s or group’s probability is calculated as:
Probability = (Roll Numerator) / (Roll Denominator)
This system ensures that probabilities scale dynamically when you add or modify items or classifier options, maintaining balance without recalibration.
Classifier Options and Group-Level Control
In addition to assigning numerators to individual items, you can also assign numerators to classifier options. This allows you to manage probabilities at a group level. For example, you can control how often items of a particular rarity drop without defining individual item probabilities.
Example Configuration
Classifier: Rarity
| Classifier Option | Roll Numerator | Probability |
|---|---|---|
Common | 70 | 70 / 120 = 58.33% |
Uncommon | 30 | 30 / 120 = 25.00% |
Rare | 15 | 15 / 120 = 12.50% |
Legendary | 5 | 5 / 120 = 4.17% |
Roll Denominator: ( 70 + 30 + 15 + 5 = 120 )
This configuration controls how often items from each rarity classification are rolled.
Combining Classifier Options and Items
You can assign numerators to both classifier options and individual items for more granular control.
Example: Rarity with Items
| Rarity | Item | Roll Numerator | Probability |
|---|---|---|---|
Common | Sword | 50 | 50 / 100 = 50.00% |
Shield | 50 | 50 / 100 = 50.00% | |
Uncommon | Potion | 30 | 30 / 30 = 100.00% |
Roll Denominator for Rarity: ( 70 + 30 = 100 )
Roll Denominator for Common Items: ( 50 + 50 = 100 )
If a Common rarity is rolled, there’s an equal 50% chance of getting a Sword or a Shield.
Using classifier options and item-level numerators together allows you to define probabilities at both the group and item level, providing maximum flexibility for your loot system.
Practical Applications
- Group-Level Control: Use classifier options like rarity to control probabilities across a category of items.
- Granular Probabilities: Assign numerators to individual items for precise control within a group.
- Dynamic Scaling: Easily add new classifier options or items without recalibrating the entire loot system.
Best Practices
- Combine Group and Item Control: Use classifier options for high-level probability control and item numerators for fine-tuning within groups.
- Test for Balance: Ensure your roll numerators reflect desired rarity distributions and are balanced for gameplay.
- Use Intuitive Values: Keep numerators simple and consistent (e.g., 10, 50, 100) to make scaling straightforward.
Example Use Case: Treasure Chest Drops
Imagine a treasure chest with the following configuration:
Classifier: Rarity
| Classifier Option | Roll Numerator | Probability |
|---|---|---|
Common | 70 | 70 / 170 = 41.18% |
Uncommon | 50 | 50 / 170 = 29.41% |
Rare | 30 | 30 / 170 = 17.65% |
Legendary | 20 | 20 / 170 = 11.76% |
Items within Rarities
| Rarity | Item | Roll Numerator | Probability |
|---|---|---|---|
Common | Gold Coins | 50 | 50 / 100 = 50.00% |
Shield | 50 | 50 / 100 = 50.00% | |
Legendary | Excalibur | 100 | 100 / 100 = 100.00% |
Roll Denominator for Rarity: ( 70 + 50 + 30 + 20 = 170 )
Roll Denominator for Common Items: ( 50 + 50 = 100 )
This configuration ensures balanced probabilities for both rarities and items within each rarity.
By using roll numerators for classifier options and items, Forge enables dynamic, scalable, and flexible probability systems that adapt to your game’s evolving needs.