3D 공룡 달리기 - 원형 배치와 절차적 맵 생성

This tutorial covers two systems from the 3D dino runner: DinoPositionController (arrange multiple dinos evenly around a circle using trigonometry) and MapManager (chain map prefabs end-to-end to build a random course procedurally). Along the way you will understand Mathf.Cos/Sin, Mathf.Deg2Rad, GetComponent on prefabs at runtime, and the difference between Euler angles and Quaternions.

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Game Structure

Script	Role
DinoPositionController	Place dinos evenly on a circle
Map	Returns the Z length of one map segment
MapManager	Chains 5 random map prefabs end-to-end at startup

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DinoPositionController – Circular Arrangement

Full Code

using UnityEngine;

public class DinoPositionController : MonoBehaviour
{
    public Transform raptors;   // Parent Transform holding all dinos as children
    public float radius = 1f;   // Circle radius
    public float ratio = 0.1f;  // Angle gap multiplier

    void Start()
    {
        SetDinoPosition();
    }

    private void SetDinoPosition()
    {
        for (int i = 0; i < raptors.childCount; i++)
        {
            if (i > 8)
            {
                raptors.GetChild(i).gameObject.SetActive(false);
                continue;
            }

            if (raptors.childCount < 10)
            {
                float angleStep = 360f / (raptors.childCount * ratio);
                float angle = i * angleStep;
                float angleRad = angle * Mathf.Deg2Rad;

                float x = Mathf.Cos(angleRad) * radius;
                float z = Mathf.Sin(angleRad) * radius;

                raptors.GetChild(i).localPosition = new Vector3(x, 0f, z);
            }
        }
    }
}

Key Concepts

1. Trigonometry for circular placement

A point on a circle of radius r at angle θ:

x = cos(θ) × r
z = sin(θ) × r

float angleStep = 360f / (raptors.childCount * ratio);
float angle = i * angleStep;
float angleRad = angle * Mathf.Deg2Rad;

float x = Mathf.Cos(angleRad) * radius;
float z = Mathf.Sin(angleRad) * radius;

raptors.GetChild(i).localPosition = new Vector3(x, 0f, z);

• angleStep: Divides 360° by the number of dinos so they are spaced evenly. ratio lets you tighten or widen the spacing.
• Mathf.Deg2Rad: The constant π / 180 (≈ 0.01745). Multiply degrees by this to get radians. Unity's trig functions (Cos, Sin) require radians.
• Mathf.Cos / Mathf.Sin: Return the cosine/sine of a radian angle. Multiplying by radius gives the point on the circle.
• localPosition: Sets the position relative to the parent raptors Transform.

Example — 4 dinos, radius = 2, ratio = 1:

i	angle	x	z
0	0°	2	0
1	90°	0	2
2	180°	−2	0
3	270°	0	−2

2. GetChild – access children by index

raptors.GetChild(i).localPosition = new Vector3(x, 0f, z);
raptors.GetChild(i).gameObject.SetActive(false);

• transform.GetChild(index): Returns the child Transform at the given index (0-based, up to childCount - 1).
• SetActive(false): Deactivates the GameObject — invisible, no Update, but still in the hierarchy.
• Dinos beyond index 8 (9th and above) are deactivated to cap the displayed count at 9.

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Map – Segment Length

Full Code

using UnityEngine;

public class Map : MonoBehaviour
{
    public Vector3 mapSize;

    public float GetMapSize()
    {
        return mapSize.z;
    }
}

• Attached to every map prefab. GetMapSize() returns the segment's Z length so MapManager can chain them correctly.
• Set mapSize.z in the Inspector to match the actual Z size of each map prefab.

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MapManager – Procedural Map Generation

Full Code

using UnityEngine;

public class MapManager : MonoBehaviour
{
    public GameObject[] mapPrefabs;

    void Start()
    {
        Vector3 mapPosition = Vector3.zero;
        Transform generatedMapsParent = GameObject.Find("GeneratedMaps").transform;

        for (int i = 0; i < 5; i++)
        {
            GameObject selectedMap = mapPrefabs[Random.Range(0, mapPrefabs.Length)];

            mapPosition.y = selectedMap.transform.position.y;

            if (i > 0)
            {
                mapPosition.z += selectedMap.GetComponent<Map>().GetMapSize() / 2f;
            }

            GameObject nowMap = Instantiate(selectedMap, mapPosition, Quaternion.identity, generatedMapsParent);

            mapPosition.z += nowMap.GetComponent<Map>().GetMapSize() / 2f;
        }
    }
}

Key Concepts

1. Chaining map segments end-to-end

Each prefab's pivot is at its center, so placing the next map requires advancing by half the current segment plus half the next segment:

[Map A center] ←A/2→ [A end = B start] ←B/2→ [Map B center]

// Advance to center of the current map (skip on first iteration — no previous map)
mapPosition.z += selectedMap.GetComponent<Map>().GetMapSize() / 2f;

// Place the map
GameObject nowMap = Instantiate(selectedMap, mapPosition, Quaternion.identity, generatedMapsParent);

// Advance to where the next map's center will be
mapPosition.z += nowMap.GetComponent<Map>().GetMapSize() / 2f;

2. GetComponent on a prefab at runtime

selectedMap.GetComponent<Map>().GetMapSize()

• Calling GetComponent<T>() on a prefab reference (not yet instantiated) reads data from the original asset.
• This is safe in Start — just be careful not to call methods that depend on scene state on un-instantiated prefabs.

3. Instantiate with a parent

GameObject nowMap = Instantiate(selectedMap, mapPosition, Quaternion.identity, generatedMapsParent);

• The fourth parameter sets the parent Transform for the new object immediately on creation, keeping the Hierarchy tidy.

4. GameObject.Find

Transform generatedMapsParent = GameObject.Find("GeneratedMaps").transform;

• GameObject.Find("name") searches the entire scene by name. Call it once in Start and cache the result — repeated searches each frame are expensive.
• Returns null if the object does not exist, so make sure a GameObject named "GeneratedMaps" is present in the scene.

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Euler Angles vs Quaternions

Quaternion.identity appears in every Instantiate call above. Here is why Quaternions are used instead of Euler angles.

Euler Angles

Rotation expressed as three axis angles (degrees):

transform.eulerAngles = new Vector3(30f, 45f, 0f);
transform.Rotate(0f, 90f, 0f);

• Pros: Intuitive, easy to read in Inspector.
• Con – Gimbal Lock: When one axis reaches 90°, two axes align and you lose one degree of rotational freedom. For example, rotating Y to 90° makes X and Z identical, preventing rotation in one direction.
• Con – Order-dependent: Unity applies Euler rotations in ZXY order; the result changes depending on order.

Quaternions

Four-component mathematical structure (w, x, y, z) that represents rotation without gimbal lock:

Quaternion.identity             // No rotation
Quaternion.Euler(30f, 45f, 0f)  // Convert Euler to Quaternion
Quaternion.LookRotation(dir)    // Rotate to face a direction
Quaternion.Slerp(a, b, t)       // Smooth interpolation between two rotations

	Euler Angles	Quaternion
Representation	(X°, Y°, Z°)	(w, x, y, z)
Readability	High	Low
Gimbal lock	Possible	None
Interpolation	Can snap	Smooth (Slerp)
Unity internal	Converted to Quaternion	Used directly

Best practice: Enter rotation values as Euler via Quaternion.Euler(), and use Quaternion.Slerp() for smooth animated rotation.

// Smoothly rotate toward a target rotation
transform.rotation = Quaternion.Slerp(
    transform.rotation,
    Quaternion.Euler(0f, 90f, 0f),
    Time.deltaTime * rotateSpeed
);

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Scene Setup Summary

Item	Recommendation
Dino parent	Empty GameObject with DinoPositionController; assign dino parent Transform
Map prefabs	Attach Map.cs to each prefab; set mapSize.z to match actual Z length
MapManager	Empty GameObject with MapManager; fill mapPrefabs array in Inspector
GeneratedMaps	Empty GameObject named exactly "GeneratedMaps" — parent of all spawned maps