Table of Contents

Procedural Mesh Guide

Learn how to generate meshes at runtime using S1MAPI's fluent API.

Creating Basic Shapes

The ProceduralMeshBuilder class provides methods for creating common geometric shapes:

Box

// Simple box at origin, 1 meter cube
GameObject cube = new ProceduralMeshBuilder("Cube")
    .AddBox(Vector3.zero, Vector3.one)
    .Build();

// Box at custom position and size
GameObject box = new ProceduralMeshBuilder("MyBox")
    .AddBox(new Vector3(5, 2, 3), new Vector3(2, 1, 3))
    .Build();

Sphere

// Low-poly sphere (few subdivisions = blocky)
GameObject lowPolySphere = new ProceduralMeshBuilder("LowPoly")
    .AddSphere(Vector3.zero, 0.5f, subdivisions: 4)
    .Build();

// Smooth sphere (default subdivisions = 12)
GameObject smoothSphere = new ProceduralMeshBuilder("Smooth")
    .AddSphere(new Vector3(0, 1, 0), 1.0f)
    .Build();

Cylinder

// Vertical cylinder from point A to B
Vector3 bottom = new Vector3(0, 0, 0);
Vector3 top = new Vector3(0, 3, 0);

GameObject cylinder = new ProceduralMeshBuilder("Pillar")
    .AddCylinder(bottom, top, radius: 0.2f, segments: 8)
    .Build();

Capsule

// Capsule = cylinder + two hemispheres
Vector3 bottom = new Vector3(0, 0, 0);
Vector3 top = new Vector3(0, 2, 0);

GameObject capsule = new ProceduralMeshBuilder("Capsule")
    .AddCapsule(bottom, top, radius: 0.3f)
    .Build();

Combining Shapes

Chain multiple shape methods to create complex geometries:

GameObject tower = new ProceduralMeshBuilder("Tower")
    .AddCylinder(new Vector3(0, 0, 0), new Vector3(0, 2, 0), 0.3f, 8)     // Base cylinder
    .AddSphere(new Vector3(0, 2.3f, 0), 0.4f, 6)                          // Top sphere
    .SetColor(Color.gray)
    .Build();

Applying Materials and Colors

Set a Specific Material

Material metalMaterial = MaterialPresets.Metal(Color.gray, metallic: 0.9f);

GameObject metalBox = new ProceduralMeshBuilder("MetalBox")
    .AddBox(Vector3.zero, Vector3.one)
    .SetMaterial(metalMaterial)
    .Build();

Set a Solid Color

GameObject redBox = new ProceduralMeshBuilder("RedBox")
    .AddBox(Vector3.zero, Vector3.one)
    .SetColor(Color.red)
    .Build();

// Custom color
Color purple = new Color(0.5f, 0, 0.5f);
GameObject purpleSphere = new ProceduralMeshBuilder("PurpleSphere")
    .AddSphere(Vector3.zero, 0.5f)
    .SetColor(purple)
    .Build();

Flat Shading

Apply flat shading for a low-poly aesthetic:

GameObject lowPolyTree = new ProceduralMeshBuilder("LowPolyTree")
    .AddCylinder(new Vector3(0, 0, 0), new Vector3(0, 1, 0), 0.2f, 6)    // Trunk
    .AddSphere(new Vector3(0, 1.5f, 0), 1.0f, subdivisions: 4)           // Foliage
    .SetColor(new Color(0.3f, 0.5f, 0.2f))
    .ApplyFlatShading()
    .Build();

Building Without a GameObject

If you only need the Mesh object (not a GameObject):

Mesh mesh = new ProceduralMeshBuilder("MyMesh")
    .AddBox(Vector3.zero, Vector3.one)
    .AddSphere(new Vector3(2, 0, 0), 0.5f)
    .BuildMesh();

// Use the mesh manually
MeshFilter filter = gameObject.AddComponent<MeshFilter>();
filter.mesh = mesh;

MeshRenderer renderer = gameObject.AddComponent<MeshRenderer>();
renderer.material = MaterialPresets.Opaque(Color.blue);

Example: Complete Object

using S1MAPI.ProceduralMesh;
using S1MAPI.Utils;
using UnityEngine;

public static class ProceduralObjects
{
    public static GameObject CreateCrate(Vector3 position, Color woodColor)
    {
        return new ProceduralMeshBuilder("WoodenCrate")
            .AddBox(Vector3.zero, new Vector3(1, 1, 1))              // Main body
            .AddBox(new Vector3(0, 0.51f, 0), new Vector3(1.05f, 0.05f, 1.05f))  // Lid rim
            .SetColor(woodColor)
            .ApplyFlatShading()
            .Build();
    }

    public static GameObject CreateBeacon(Vector3 position)
    {
        // Metal pole
        GameObject beacon = new ProceduralMeshBuilder("Beacon")
            .AddCylinder(position, position + Vector3.up * 3, 0.1f, 8)
            .SetMaterial(MaterialPresets.Metal(Color.gray))
            .Build();

        // Glowing light at top
        GameObject light = new ProceduralMeshBuilder("BeaconLight")
            .AddSphere(position + Vector3.up * 3.2f, 0.2f, 6)
            .SetMaterial(MaterialPresets.Emissive(Color.yellow, intensity: 3f))
            .Build();

        light.transform.SetParent(beacon.transform);

        return beacon;
    }
}

Performance Tips

  1. Combine shapes: Adding multiple shapes to one builder is more efficient than creating separate meshes.

  2. Use flat shading wisely: Flat shading requires recalculating normals. Apply it only when needed.

  3. Consider vertex limits: Unity's Mesh uses 16-bit indices by default (65,535 vertices). For larger meshes, set mesh.indexFormat = UnityEngine.Rendering.IndexFormat.UInt32.

Next Steps

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