RandomSpawnCharacters

Sample Scene Setup

Figure 1. Example of assigned spawn areas and object pool setup.

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Overview

The RandomSpawnCharacters component is responsible for randomly placing child objects (for example, characters, agents, or NPCs) that exist in an object pool within predefined spawn areas under the component's GameObject.

Each child area under this component defines a region where characters can appear. The script uses the area size of each region to weight the probability of selection — meaning larger areas are more likely to receive more characters.

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Component Responsibilities

• Collects all child area Transforms under the component
• Collects all pooled objects (for example, humans) from the assigned ObjectPool
• Calculates each area's relative area weight based on its local scale
• Spawns (or repositions) each human within one of the weighted child areas
• Repeats the sampling at a fixed interval using Unity's FixedUpdate loop

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Serialized Fields

Field	Type	Description
ObjectPool	Transform	The parent transform containing pooled objects (for example, humans or NPCs). Each child under this pool will be repositioned.
eachPosWaitFrame	int	The number of frames to wait between each reposition cycle (in FixedUpdate). Default is 4 frames.

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Internal Variables

Variable	Type	Description
childAreas	Transform[]	Stores all the child transforms under the component. These define the spawn areas.
humans	LineOfSight[]	References to all characters inside the object pool.
areaWeights	float[]	Normalized area weights used for random area selection.
timer	int	Frame-based timer for controlling update intervals.

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Script Flow

1. Initialization (Awake)

• Retrieves all child areas under this GameObject
• Retrieves all human agents under the ObjectPool
• Calculates area weights via CalculateAreaWeights()

2. Area Weight Calculation

• Each child area contributes proportionally to its surface area (scale.x * scale.z)
• Weights are normalized to ensure they sum to 1
• Larger areas have a higher chance of selection

3. Random Section Selection

• Uses a weighted random algorithm (GetWeightedRandomSection) to pick which area to place each human in

4. Character Placement

For each human: - Chooses a random point within the selected area's bounds - Applies the area's local rotation - Translates the position into world space

5. Continuous Update

In FixedUpdate, the code checks if the frame count exceeds the wait threshold and re-samples all character positions accordingly.

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Usage Guide

1. Attach RandomSpawnCharacters to a GameObject (for example, SpawnManager)
2. Create child GameObjects under it to define spawn areas. Adjust each child's Transform.localScale to represent area size
3. Assign an ObjectPool Transform that contains all characters to be placed
4. Set eachPosWaitFrame if you want to adjust the update frequency

Tip

Ensure all pooled objects have a LineOfSight component (or adjust the script for your component type).

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Example Scene Setup

SpawnManager (with RandomSpawnCharacters)
 ├── Area_1 (Transform defines spawn area)
 ├── Area_2 (Transform defines spawn area)
 └── Area_3 (Transform defines spawn area)

ObjectPool
 ├── Human_1 (LineOfSight)
 ├── Human_2 (LineOfSight)
 └── Human_3 (LineOfSight)

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Notes

• The system assumes rectangular spawn regions (x * z)
• Y-axis height is ignored (flat plane assumption)
• The parent transform is excluded from spawn area calculations
• You can extend the script to support:
  • Non-rectangular areas
  • Custom randomization patterns
  • Weighted spawn limits per area

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