Object throw velocity

Help and Feedback Scripting Support
#1

Hello. I made a grab system with the ability to throw an object, but light objects are thrown too hard, or, on the contrary, weakly. Video below.

I want to make the throw speed adjustable depending on the weight of the object. The code is below.

local grabEvent = script.Parent.GrabEvent

local up = false
local curObject

local hrp = script.Parent.Parent:WaitForChild("HumanoidRootPart")

function changePos(alignPos:AlignPosition)
	repeat alignPos.Position = script.Parent.GrabPart.Position	
		wait()
	until up
end

grabEvent.OnServerEvent:Connect(function(plr, act, object)
	if act == "GrabStart" then
		up = false
		curObject = object
		local alignPosition = Instance.new("AlignPosition", object)
		alignPosition.Attachment1 = script.Parent.GrabPart.Attachment
		local density = object.CurrentPhysicalProperties.Density/2.5
		alignPosition.Responsiveness = 100*2/density
		alignPosition.ApplyAtCenterOfMass = true
		local att2 = Instance.new("Attachment", curObject)
		att2.Name = "GrabAtt"
		alignPosition.Attachment0 = att2
		
	elseif act == "GrabEnd" then
		up = true
		curObject:FindFirstChild("AlignPosition"):Destroy()		
		curObject:FindFirstChild("GrabAtt"):Destroy()
	elseif act == "Camera" then
		script.Parent.GrabPart.CFrame = object
	elseif act == "Throw" then
		up = true
		local alignPos = curObject:FindFirstChild("AlignPosition")
		alignPos.Attachment0:Destroy()
		alignPos:Destroy()
		local density = curObject.CurrentPhysicalProperties.Density/2.5
		curObject.Velocity = script.Parent.GrabPart.CFrame.LookVector * 50/density
		curObject = nil
	end
end)

The code hasn’t been polished yet, so don’t be surprised.

#2

You’re applying velocity directly, which doesn’t account for mass of the object. If you want the items to be thrown at the same ‘speed’, just set the velocity directly:

local speedOfThrow = 50
curObject.Velocity = script.Parent.GrabPart.CFrame.LookVector * speedOfThrow

By dividing by density, you’re reducing the throw velocity as the part becomes more dense.

If you wish for a system where objects get thrown more-or-less based on their size/weight, use the part’s mass as that will take into account both density and volume (Mass = Density * Volume).

local impulse = script.Parent.GrabPart.CFrame.LookVector * (throwPower / curObject:GetMass())
curObject:ApplyImpulse(impulse)

Edit: ApplyImpulse might already consider the part’s mass (I can’t remember). If you’re getting incorrect results, simply replace the line with local impulse = script.Parent.GrabPart.CFrame.LookVector * throwPower

#3

the impulse method helped (it automatically consider the mass)

Can you help with the AlignPosition part? I need to adjust Responsiveness depending on the mass.

#4

If it’s just responsiveness, then replacing density with part:GetMass() should solve most of your issues. You may need to re-adjust your scaling factor (100*2) to account for the different values.

Also could be worth math.clamp()ing the value to ensure you don’t get ridiculously high or low responsiveness values if the part is massive or tiny.