tokyo-wangan-racing/docs/MESH_SWAP.md

Swapping the placeholder RX-7 for the real mesh (M1)

Right now every car is a coloured block + a VehicleSeat so the game is drivable today. This is the one file you touch to make the RX-7 a real model: src/server/CarManager.luau → the buildCarModel function.

Nothing else (saving, the allowlist, car switching, the map, anti-cheat) needs to change. That's the whole point of isolating model-building in one function.

Reference photos

The real car's reference photos live on the NAS (too large to commit to git):

unraid-1:/mnt/user/data/yy-roblox-games/0-fast-n-furious-sim/001-1993 Mazda RX-7/

A single downscaled reference is included at assets/reference/rx7-reference.png for quick lookups.

Step 1 — Get a model into Roblox

Options, easiest first:

1. Buy or find a free RX-7 FD model on the Roblox Creator Marketplace/toolbox, or
2. Model it in Blender from the reference photos and import the mesh (.fbx/.obj) via Studio's 3D importer, or
3. Commission one.

You want a single Model whose parts are welded together, with a clear "body" part you can drive. Keep the part count low (mobile perf).

Step 2 — Store it where Rojo/Studio can clone it

Put the finished Model under ReplicatedStorage (e.g. a CarModels folder). Two ways to manage it:

• Simple: keep it in the Studio place file as a real Instance (not synced by Rojo). Fine for a single hero car.
• Version-controlled: export the model to a .rbxm and reference it from the Rojo project so it lives in git. See Rojo's $path docs for .rbxm model files.

Step 3 — Rewrite buildCarModel to clone the real mesh

Replace the block-building body of buildCarModel(car, maxSpeed, torque, turnSpeed) with something like:

local CAR_MODELS = ReplicatedStorage:WaitForChild("CarModels")

local function buildCarModel(car, maxSpeed, torque, turnSpeed)
    -- Look up a real model by car id; fall back to the block builder if missing.
    local template = CAR_MODELS:FindFirstChild(car.Id)
    if not template then
        return buildBlockCar(car, maxSpeed, torque, turnSpeed) -- keep the old code as a fallback
    end

    local model = template:Clone()

    -- Ensure it has a VehicleSeat named "DriveSeat" welded to the driving body.
    local seat = model:FindFirstChild("DriveSeat")
    if not seat then
        seat = Instance.new("VehicleSeat")
        seat.Name = "DriveSeat"
        -- weld seat to model.PrimaryPart, position it in the cabin...
        seat.Parent = model
    end
    seat.MaxSpeed = maxSpeed
    seat.Torque = torque
    seat.TurnSpeed = turnSpeed

    assert(model.PrimaryPart, "Car model needs a PrimaryPart set")
    return model
end

Keep the current block-builder renamed as buildBlockCar so any car without a real mesh still works. That way you can import cars one at a time.

Step 4 (recommended, M1) — Move to a real chassis

The VehicleSeat is great for "it drives today" but for real suspension/grip, adopt a proven constraint chassis (A-Chassis or a modern equivalent). At that point buildCarModel clones the chassis rig and attaches the RX-7 body to it. Still one function; still no changes elsewhere.

Verify

• rojo build --output build.rbxl compiles.
• In Studio: Play → you spawn in the real RX-7 → it drives → it saves.
• Non-allowlisted test account still can't select the RX-7 (server enforced).