PI Placement System

Download Example: https://mega.nz/#!8g5XlSqb!lbRigilYpDbdOupfc80AwavoQ9n-F0faCjC3MjmK5wE

local run_service = game:GetService("RunService")
local anchor_name = workspace.Anchor_Part -- Anchor Part's name
local tile_folder = workspace.Tiles -- where will the tiles be placed inside?
local scan_distance = 500 -- how many studs away will the placement system scan?
local x_lim,z_lim = 512,512 -- how far away from the anchor will you let the player place?
local Mouse_Offset = Vector3.new(-2,0,-2) -- offset vector3 of mouse placement
local smooth_placement = true -- PI's smooth placement system? true for yes, false for no
local rotation = 0 -- edit this value in your input script to change rotation

-- safely return player
function getLocalPlayer()
    if not game.Players.LocalPlayer then
        repeat wait() until game.Players.LocalPlayer -- halt until player found
    end
    return game.Players.LocalPlayer
end

-- safely return character
function getLocalCharacter()
    local pl = getLocalPlayer()
    if not pl.Character then
        repeat wait() until pl.Character -- halt until character exists
    end
    return pl.Character
end

function round(x) return math.floor(x+0.5) end
function onr(r,c,v3) if r==c then return v3 end end
local foo, fof, oof, none = Vector3.new(4,0,0), Vector3.new(4,0,4), Vector3.new(0,0,4), Vector3.new(0,0,0)
function GetOffset(Size,r)
    -- rotation fix, will determine Vector3 offset for less weird rotation
    local a = Vector3.new(round(Size.X),round(Size.Y),round(Size.Z))/4

    local ax=a.X%2 local az=a.Z%2
    local pick
    if ax == 0 and az == 0 then -- 0 0 offset
        pick = onr(r,0,none) or onr(r,90,none) or onr(r,180,none) or onr(r,270,none)
        return pick
    elseif ax == 0 and az == 1 then -- 0 1 offset
        pick = onr(r,0,none) or onr(r,90,foo) or onr(r,180,oof) or onr(r,270,none)
        return pick
    elseif ax == 1 and az == 0 then -- 1 0 offset
        pick = onr(r,0,oof) or onr(r,90,foo) or onr(r,180,fof) or onr(r,270,fof)
        return pick
    else -- 1 1 offset
        pick = onr(r,0,none) or onr(r,90,foo) or onr(r,180,fof) or onr(r,270,oof)
        return pick
    end
end
function modelPutty(x)
    -- this will "Putty" the model, which will make it transparent
    for _,c in pairs(x:GetChildren()) do
        if (c:IsA("BasePart") or c:IsA("UnionOperation")) and not c:FindFirstChild("PuttyTransparency") and c.Name ~= "Upgrader" then
            local v = Instance.new("NumberValue",c)
            v.Name = "PuttyTransparency"
            v.Value = c.Transparency
            local v2 = Instance.new("BoolValue",c)
            v2.Name = "PuttyCollidable"
            v2.Value = c.CanCollide
            c.CanCollide = false
            if c.Name:find("Marker")==nil then
                c.Transparency = math.min(c.Transparency + 0.5,1)
            end
        end
        if c.Name:find("Marker")==nil then
            modelPutty(c)
        end
    end
end
function modelUnputty(x)
    -- make model visible again, but wont be needed for placement
    for _,c in pairs(x:GetChildren()) do
        if (c:IsA("BasePart") or c:IsA("UnionOperation")) and c:FindFirstChild("PuttyTransparency") then
            c.Transparency = c.PuttyTransparency.Value
            c.CanCollide = c.PuttyCollidable.Value
            c.PuttyTransparency:Destroy()
            c.PuttyCollidable:Destroy()
        end
    end
end

UIS = game:GetService"UserInputService"
local key_map = { -- change key_map if your game needs different keys
    cancel_placement = {
        Keyboard={'Q'},
        OnPress = function()
            if selected_model then
                selected_model:Destroy()
            end
            selected_model = nil
        end
    },
    rotate = {
        Keyboard={'R'},
        OnPress = function()
            rotation = (rotation + 90) % 360 -- reset at 360
        end
    },
    test_model = {
        Keyboard={'E'},
        OnPress = function()
            print'select'
            if selected_model then
                selected_model:Destroy()
            end
            selected_model = workspace.Test_Model:Clone()
            modelPutty(selected_model)
            selected_model.Parent = workspace.CurrentCamera
        end
    },
}
UIS.InputBegan:connect(function(Key)
    local UType,Key_Code = Key.UserInputType.Name,Key.KeyCode.Name
    for key_name,key_data in pairs(key_map) do
        if key_data[UType] then -- cancel
            for i = 1, #key_data[UType] do
                if key_data[UType][i]==Key_Code then
                    key_data.OnPress(Key)
                end
            end
        end
    end
end)

while run_service.RenderStepped:wait() do

    --[[ requirements:
    1) selected_model MUST have PrimaryPart
    2) There MUST be an AnchorPart in workspace on which the grid will be placed
    3) There MUST be a RemoteEvent / RemoteFunction hooked up for when you click
        (You shouldnt use experimental mode anyways)
    4) ALL PLACED TILES MUST BE PLACED IN TILE_FOLDER!!!!!
        (Else your mouse will weirdly register where the model will be placed)
    ]]
    mouse = getLocalPlayer():GetMouse()
    while selected_model and selected_model.PrimaryPart do
        local ppart = selected_model.PrimaryPart
        -- initial scan of mouse's ray
        local Mouse_Ray = Ray.new(mouse.UnitRay.Origin, mouse.UnitRay.Direction * scan_distance)
        intersect_part, Hit = workspace:FindPartOnRayWithIgnoreList(Mouse_Ray, {workspace.CurrentCamera, tile_folder, getLocalCharacter()})
        Hit = Hit + Mouse_Offset
        -- secondary scan of model position
        local ray = Ray.new(ppart.CFrame.p, Vector3.new(0,-20,0))
        local testpart = workspace:FindPartOnRayWithIgnoreList(ray, {workspace.CurrentCamera, tile_folder, getLocalCharacter()})
        -- return model's offset based on rotation
        local moffset = Vector3.new(0,0,0)
        moffset = GetOffset(ppart.Size, rotation)
        -- offset from anchor
        local diff = Hit - anchor_name.Position
        -- 'Valid' doesnt matter if there is no intersect_part, so include it in the checks
        local XValid,ZValid=math.abs(diff.X)<=x_lim,math.abs(diff.Z)<=z_lim
        local movePos
        if intersect_part and XValid and ZValid then -- must be 'Valid'+'part'
            -- primary part's size x and z determine its offset for placement
            local psx,psz=ppart.Size.X/2,ppart.Size.Z/2
            local mousePos = Vector3.new(round(Hit.X/4)*4, 0, round(Hit.Z/4)*4)
            -- 1) calculate position you want the model to go
            local look = CFrame.new(mousePos)
                        * CFrame.Angles(0, -math.rad(rotation), 0)
                        * CFrame.new(-psx%4, 0, -psz%4)
                        + moffset
            local cf2
            -- 2) change by any offsets, plus the primarypart's Y size
            cf2=look+Vector3.new(0,(ppart.Size.Y/2),0)
            -- this variable is used for smooth placement
            local dist = (cf2.p-selected_model.PrimaryPart.CFrame.p).magnitude
            placecframe = cf2
            if (dist<.2) or (dist>64) then
                -- too close or too far, teleport to goal cframe
                selected_model:SetPrimaryPartCFrame(cf2)
            else
                -- smoothly move to goal cframe
                selected_model:SetPrimaryPartCFrame(ppart.CFrame:lerp(cf2,((not smooth_placement) and 1) or .6)) --.4
            end
        end
        run_service.RenderStepped:wait()
    end

end