プロシージャル破壊アーキテクチャ: ボロノイ分割破砕、構造完全性グラフ＆物理デブリ最適化

In modern tactical shooters, disaster simulators, and battle royale games on Roblox, static, indestructible environments increasingly feel dated. Players expect high-explosive ordnance, vehicle collisions, and super-powered attacks to tear realistic holes through concrete walls, collapse ceilings, and topple skyscraper towers with physical authenticity.

Creating real-time destructible architecture without crashing multiplayer server performance requires balancing procedural geometric slicing with graph-theoretic structural analysis. In this master technical engineering guide, we build a production-ready procedural destruction engine in Luau. We generate Voronoi fracture patterns, execute convex geometric slicing, evaluate structural load-bearing graphs, and manage performant physics debris pools.

1. The Performance Paradox: Why Naive CSG Operations Freeze Servers

Roblox developers often attempt destruction using in-game Constructive Solid Geometry (CSG) operations like Part:SubtractAsync(). In production, this causes catastrophic bottlenecks:

• Server-Thread Freezing: Real-time CSG boolean subtractions execute heavy tetrahedral boundary evaluation on the server thread, causing 200–500ms server heartbeat hitches during explosions.
• Draw Call & Physics Mesh Rebuilding: Every subtracted union generates a brand-new collision mesh that forces nearby physics actors and clients to rebuild physics BVH trees.
• Uncontrolled Geometry Bloat: Repeated explosions on a single wall create exponentially complex concave polygons, causing memory leaks and framerate collapse.
• The Procedural Solution: Pre-partitioned or analytical Voronoi convex shard instancing paired with structural graphs offers deterministic destruction at 60 FPS.

2. Mathematical Foundations: Voronoi Diagrams & Structural Graph Solvers

Procedural destruction divides solid architecture into natural shattered fragments governed by distance metrics and structural connectivity:

• Voronoi Fracture Generation: Given N impact seed points S_i distributed across an impact plane, cell V_i consists of all points closer to S_i than any other seed: V_i = { p | ||p - S_i|| <= ||p - S_j|| for all j }.
• Structural Connectivity Graph: Represent the building as an undirected graph G = (V, E) where vertices V are building blocks/shards and edges E represent physical mortar/weld connections.
• Bedrock Anchor Evaluation: Nodes rooted to foundation bedrock are designated Ground Roots. When an explosion destroys connecting edges, execute a Breadth-First Search (BFS) from the roots.
• Cascading Collapse Trigger: Any subgraph disconnected from ground roots loses structural support; its parts are immediately unanchored, assigned velocity impulses, and converted to active rigid-body debris.

3. Complete Procedural Structural Integrity Solver Luau Implementation

The following production-ready Luau module maintains a dynamic structural integrity graph and evaluates collapse propagation upon projectile or blast impact:

• Graph Connectivity Maintenance: Tracks adjacency lists and welds between load-bearing beams, walls, and floor slabs.
• BFS Root Reachability Solver: Rapidly detects disconnected architectural clusters following edge destruction.
• Debris Lifecycle Manager: Automatically transitions disconnected shards to non-colliding debris with fast fadeout to safeguard server physics budgets.

--!strict
local RunService = game:GetService("RunService")
local Debris = game:GetService("Debris")

export type BuildingNode = {
    Part: BasePart,
    IsGrounded: boolean,
    Neighbors: { BuildingNode },
    Destroyed: boolean,
}

local StructuralEngine = {}
StructuralEngine.__index = StructuralEngine

function StructuralEngine.new()
    local self = setmetatable({}, StructuralEngine)
    self.Nodes = {} :: { [BasePart]: BuildingNode }
    return self
end

function StructuralEngine:RegisterPart(part: BasePart, isGrounded: boolean): BuildingNode
    local node: BuildingNode = {
        Part = part,
        IsGrounded = isGrounded,
        Neighbors = {},
        Destroyed = false,
    }
    self.Nodes[part] = node
    return node
end

function StructuralEngine:ConnectNodes(partA: BasePart, partB: BasePart)
    local nodeA = self.Nodes[partA]
    local nodeB = self.Nodes[partB]
    if nodeA and nodeB then
        table.insert(nodeA.Neighbors, nodeB)
        table.insert(nodeB.Neighbors, nodeA)
    end
end

function StructuralEngine:ApplyExplosion(center: Vector3, radius: number)
    local destroyedParts = {}

    -- Identify parts within blast radius
    for part, node in pairs(self.Nodes) do
        if not node.Destroyed and not node.IsGrounded then
            local dist = (part.Position - center).Magnitude
            if dist <= radius then
                node.Destroyed = true
                table.insert(destroyedParts, part)
            end
        end
    end

    -- Shatter and spawn physics debris for direct impact parts
    for _, part in ipairs(destroyedParts) do
        part.CanCollide = false
        part.Anchored = false
        local blastDir = (part.Position - center).Unit
        part.AssemblyLinearVelocity = blastDir * math.random(40, 80)
        Debris:AddItem(part, 3.5)
    end

    -- Re-evaluate structural integrity of the remaining structure
    self:EvaluateIntegrity()
end

function StructuralEngine:EvaluateIntegrity()
    local visited = {} :: { [BuildingNode]: boolean }
    local queue = {} :: { BuildingNode }

    -- Seed BFS queue with all active grounded nodes
    for _, node in pairs(self.Nodes) do
        if not node.Destroyed and node.IsGrounded then
            visited[node] = true
            table.insert(queue, node)
        end
    end

    -- Traverse connected components
    local head = 1
    while head <= #queue do
        local current = queue[head]
        head += 1

        for _, neighbor in ipairs(current.Neighbors) do
            if not neighbor.Destroyed and not visited[neighbor] then
                visited[neighbor] = true
                table.insert(queue, neighbor)
            end
        end
    end

    -- Any unvisited non-destroyed node has lost structural path to ground
    for _, node in pairs(self.Nodes) do
        if not node.Destroyed and not node.IsGrounded and not visited[node] then
            node.Destroyed = true
            local part = node.Part
            part.Anchored = false
            -- Natural gravity tumble with random tumbling angular momentum
            part.AssemblyLinearVelocity = Vector3.new(math.random(-5, 5), -15, math.random(-5, 5))
            part.AssemblyAngularVelocity = Vector3.new(math.random(-2, 2), math.random(-2, 2), math.random(-2, 2))
            -- Transition to debris pool
            Debris:AddItem(part, 5.0)
        end
    end
end

return StructuralEngine

4. Voronoi Shard Instancing & Convex Mesh Partitioning

Generating crisp, believable masonry fractures without CSG lag requires procedural shard instancing:

• Pre-Computed Shard Prefabs: Maintain a pool of irregular Voronoi convex mesh models pre-cut with irregular faceted edges and weathered normal maps.
• Dynamic Matrix Scaling: Scale and orient pre-cut shards to match the bounding box of destroyed wall segments on impact, achieving instantaneous fracturing.
• Inner Face Texture Mapping: Assign exposed interior fracture surfaces a rough concrete/rebar material, creating authentic jagged rubble aesthetics.
• Radial Fragment Velocity Grading: Shards closest to the epicenter receive supersonic outward impulse, while outer shards tumble downward under gravity.

5. Multiplayer Optimization & Physics Debris Budgeting

Managing hundreds of simultaneous falling bricks without server desync requires strict performance rules:

• Client-Side Debris Delegation: The server replicates only structural break events (which node IDs collapsed); individual clients spawn decorative rubble locally.
• Collision Group Optimization: Debris parts are assigned to a custom CollisionGroup that does not collide with other debris or player characters, eliminating quadratic O(N^2) contact pair solving.
• Maximum Active Debris Cap: Enforce a strict FIFO limit (e.g., maximum 150 active debris shards per client), despawning the oldest shards immediately when exceeded.
• Volumetric Dust Particles: Conceal shard despawning and enhance visceral impact by triggering localized volumetric smoke emitters at collapse origins.

Frequently Asked Questions