BodyVelocity UpVector broken?

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#1

Im simply trying to create upward knockback using bodyvelocity instances, but using UoVector or even just making it like: Vector3.new(0, -100, 0) doesn’t work. Ik that bodyvelocity is deprecated but is it really broken ?

function module.BodyVelocity(charAttacking, char, kb, direction)
	local BV = Instance.new("BodyVelocity")
	BV.MaxForce = Vector3.new(5e4, 5e2, 5e4)
	
	
	if direction == "Front" then
		BV.Velocity = charAttacking.HumanoidRootPart.CFrame.LookVector * kb
	elseif direction == "Left" then
		BV.Velocity = (charAttacking.HumanoidRootPart.CFrame.RightVector * -1) * kb
	elseif direction == "Up" then
		BV.Velocity = charAttacking.HumanoidRootPart.CFrame.UpVector * kb
	end
	
	
	BV.Parent = char.HumanoidRootPart
	game.Debris:AddItem(BV, .16)
end
#2

maybe try

function module.BodyVelocity(charAttacking, char, kb, direction)
    -- Check if charAttacking and char have HumanoidRootPart
    if not charAttacking:FindFirstChild("HumanoidRootPart") then
        warn("charAttacking does not have a HumanoidRootPart.")
        return
    end
    if not char:FindFirstChild("HumanoidRootPart") then
        warn("char does not have a HumanoidRootPart.")
        return
    end

    -- Create BodyVelocity instance
    local BV = Instance.new("BodyVelocity")
    BV.MaxForce = Vector3.new(5e4, 5e4, 5e4)  -- Increase y-axis force for better movement control
    BV.Velocity = Vector3.zero  -- Default to zero velocity before setting direction

    -- Set velocity based on direction
    if direction == "Front" then
        BV.Velocity = charAttacking.HumanoidRootPart.CFrame.LookVector * kb
    elseif direction == "Left" then
        BV.Velocity = (charAttacking.HumanoidRootPart.CFrame.RightVector * -1) * kb
    elseif direction == "Up" then
        BV.Velocity = charAttacking.HumanoidRootPart.CFrame.UpVector * kb
    else
        warn("Invalid direction provided: " .. direction)
        return
    end

    -- Parent the BodyVelocity to the character's HumanoidRootPart
    BV.Parent = char.HumanoidRootPart
    
    -- Clean up the BodyVelocity after 0.16 seconds
    game.Debris:AddItem(BV, 0.16)
end
#3

You didn’t set .P, this is required for BodyVelocity to work

#4

weird cus bv works fine when using LookVector or RightVector, but for UpVector i gotta define P ?

#5

Yes, whenever I use the BodyVelocity instance it doesn’t work without a defined P

#6

I can read more into it right now

#7

Try defining a valid .P and .Velocity for the BodyVelocity and see if it works

#8

The issue you’re facing with upward knockback using the BodyVelocity instance could be due to a few different factors. Let’s walk through the potential issues and how you can fix them.

1. Deprecation of BodyVelocity:

You are correct that BodyVelocity is deprecated in Roblox, and while it’s not broken, it’s no longer recommended to use it for new projects. It’s being replaced by BodyMover objects like LinearVelocity. However, if you’re still using BodyVelocity, it should work as long as you set it up properly. If you don’t have any immediate restrictions to avoid it, we can still troubleshoot your code.

2. Setting the Velocity Properly:

Looking at your code, you are setting BV.Velocity based on the direction input. In particular, for the “Up” direction, you’re multiplying the HumanoidRootPart.CFrame.UpVector by the knockback force (kb). This should technically work to create an upward knockback, but there are a couple of things to consider:

  • The MaxForce you’re setting for BodyVelocity could limit the effect of the force you’re applying. You’re setting MaxForce = Vector3.new(5e4, 5e2, 5e4), which means the force applied in the Y (vertical) direction is much weaker than in the X and Z directions. To make sure upward knockback works properly, you should make the Y-force comparable to or stronger than the X and Z components.
  • The Velocity you’re setting needs to be realistic for the character’s mass and gravity. Roblox applies a global force (gravity) that affects everything, so if the upward knockback is too weak, the character will quickly fall due to gravity.

3. Suggestions for Improvement:

You can tweak the MaxForce values and ensure that you’re applying a proper amount of force in the Y direction to counteract gravity effectively. Here’s an improved version of your code with adjustments to MaxForce and Velocity:

Copiar código

function module.BodyVelocity(charAttacking, char, kb, direction)
    -- Create a BodyVelocity instance
    local BV = Instance.new("BodyVelocity")
    
    -- Set MaxForce with a reasonable force in all directions
    BV.MaxForce = Vector3.new(50000, 50000, 50000)  -- Increase Y force to match X and Z
    
    -- Set the velocity based on the direction
    if direction == "Front" then
        BV.Velocity = charAttacking.HumanoidRootPart.CFrame.LookVector * kb
    elseif direction == "Left" then
        BV.Velocity = (charAttacking.HumanoidRootPart.CFrame.RightVector * -1) * kb
    elseif direction == "Up" then
        BV.Velocity = charAttacking.HumanoidRootPart.CFrame.UpVector * kb
    end
    
    -- Parent the BodyVelocity to the character's HumanoidRootPart
    BV.Parent = char.HumanoidRootPart
    
    -- Clean up BodyVelocity after a short period to avoid any performance issues
    game.Debris:AddItem(BV, 0.16)
end

4. Ensure the kb Value is Sufficient:

The variable kb represents the knockback force. If kb is too small, the knockback effect may not be noticeable. Make sure that kb is large enough to have a visible effect, especially when working with vertical knockback.

5. Alternative Method (Using LinearVelocity):

As mentioned earlier, BodyVelocity is deprecated, and it’s recommended to use LinearVelocity for new projects. Here’s how you could implement a similar upward knockback effect using LinearVelocity instead:

Copiar código

function module.LinearVelocityKnockback(charAttacking, char, kb, direction)
    -- Create a LinearVelocity instance
    local LV = Instance.new("LinearVelocity")
    
    -- Set MaxForce (make sure it's high enough to apply a noticeable force)
    LV.MaxForce = Vector3.new(50000, 50000, 50000)
    
    -- Set the velocity based on the direction
    if direction == "Front" then
        LV.Velocity = charAttacking.HumanoidRootPart.CFrame.LookVector * kb
    elseif direction == "Left" then
        LV.Velocity = (charAttacking.HumanoidRootPart.CFrame.RightVector * -1) * kb
    elseif direction == "Up" then
        LV.Velocity = charAttacking.HumanoidRootPart.CFrame.UpVector * kb
    end
    
    -- Parent the LinearVelocity to the character's HumanoidRootPart
    LV.Parent = char.HumanoidRootPart
    
    -- Clean up LinearVelocity after a short period to avoid performance issues
    game.Debris:AddItem(LV, 0.16)
end

In this case, LinearVelocity works similarly to BodyVelocity but is designed for more modern physics in Roblox. It’s a better choice for new projects.

Conclusion:

  • Ensure that the MaxForce is high enough for the Y-direction to create noticeable upward knockback.
  • Use a larger value for kb to apply a more substantial force.
  • Consider switching to LinearVelocity for better performance and future-proofing.

I hope this helps to resolve the issue with upward knockback! Let me know if you have more questions.

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