Block falls through ground on spawn | block placement system

Help and Feedback Scripting Support
1

i made a preview feature for my block placement system. when i join the game, the block falls through the ground and if it gets close to any other objects including my character it also falls through too.

local collectionService = game:GetService("CollectionService")
local tweenService = game:GetService("TweenService")
local replicatedStorage = game:GetService("ReplicatedStorage")
local runService = game:GetService("RunService")
local userInputService = game:GetService("UserInputService")

local player = game.Players.LocalPlayer
local char = player.Character
local humanoid : Humanoid = char:FindFirstChild("Humanoid")
local humanoidRootPart = char:FindFirstChild("HumanoidRootPart")
local mouse = player:GetMouse()
local camera = workspace.CurrentCamera

local assets = replicatedStorage.Assets
local Temp = workspace.Temp
local Pillars = assets.Pillars
local pillar_3 = Pillars.pillar_3
local tweenInfo = TweenInfo.new(0.25)

local objToRender = nil
local raycastParams = RaycastParams.new()
raycastParams.FilterType = Enum.RaycastFilterType.Exclude
raycastParams.FilterDescendantsInstances = {char, objToRender}
--raycastParams:AddToFilter(char)

local function preparePreviewPart(object : Model)
	objToRender = object:Clone()
	objToRender.Parent = Temp

	for _, part in pairs(objToRender:GetDescendants()) do
		if part:IsA("BasePart") then
			local weld = Instance.new("WeldConstraint")
			weld.Parent = part
			weld.Part0 = objToRender.PrimaryPart
			weld.Part1 = part
			part.Transparency = 0.5
			part.CanCollide = false
			part.CanQuery = false
		end
	end
end

local function snapToGrid(position : Vector3, gridSize : number)
	return Vector3.new(
		math.floor(position.X / gridSize + 0.5) * gridSize,
		math.floor(position.Y / gridSize + 0.5) * gridSize,
		math.floor(position.Z / gridSize + 0.5) * gridSize
	)
end

local function renderPreview()
	local mouseLocation = userInputService:GetMouseLocation()
	local unitRay = camera:ViewportPointToRay(mouseLocation.X, mouseLocation.Y)
	local raycastResult = workspace:Raycast(unitRay.Origin, unitRay.Direction * 200, raycastParams)
	local canBuild = char and humanoid and humanoid.Health > 0 and humanoidRootPart

	if canBuild and raycastResult and raycastResult.Instance and objToRender then
		local targetPos = raycastResult.Position + raycastResult.Normal * (objToRender.PrimaryPart.Size.Y / 2)
		local tweenObj = tweenService:Create(
			objToRender.PrimaryPart,
			tweenInfo,
			{
				CFrame = CFrame.new(
					snapToGrid(targetPos, 1)
				)
			}
		)
		tweenObj:Play()
		tweenObj.Completed:Wait()
	end
end

preparePreviewPart(pillar_3)
runService:BindToRenderStep("Preview", Enum.RenderPriority.Camera.Value, renderPreview)
2

Simply put you need to anchor the parts in the model. I made my own placement system very recently actually and this was my issue too. While a part is unanchored the Roblox Physics engine will ALWAYS take priority, and to ensure your CFrames work properly the parts need to be anchored.

1 Like
3

fantastic! i just anchored the primary part of my model and it works perfectly. thanks a million tanner! (-:

1 Like