What is the unit of AddForce?

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Hey, I have been wondering what is the units of AddForce function?
By units I do not mean the parameters - FVector. I mean the physical units. Is it in newtons?

I need this because I have an arrow which has a target. I want the arrow to get shot and get to the target.
I did not find any material on this so I have been thinking to use physics and use AddForce function. So the question is does AddForce’s units is newtons?

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It isn’t in Newtons. You need to set very, very high values for AddForce (1M). But, you seem to be looking for AddImpulse (which also needs huge values).

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Hi Darkstorm1997,

It seems that the unit of measure is kgcms-1. This is why it requires such large numbers to provide considerable force.

However, the way that the AddForce function is intended to be used is as a continuous action instead of a one-time call. It would be best to use AddForce in a tick function to apply it over multiple frames to get the desired effect.

For more information: UPrimitiveComponent::AddForce | Unreal Engine Documentation

If you have any more questions about this topic, please let me know.

Have a nice day,

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Small correction.

F = ma, so kg * ((cm/s)/s), so it’s actually kg cm s^-2

And torque is T = r x F, so kg cm^2 s^-2

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Hi.
Can anyone from Epic please confirm whether Black Phoenix’ post is correct.
Reading the forums leaves me with a fair amount of confusion with respect to physics units in UE4. Epic has a fair potential of improvement of their docs in this respect.
Best regards.

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That was a mistake on my part. Black Phoenix is correct. You can see a confirmation from Ori at this post. Why does allowing collisions stop AddForce from working? - Character & Animation - Epic Developer Community Forums

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Thanks .

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The unreal unit of force is centinewtons (cN) - just like the unreal unit of distance is centimeters (cm).

1 centinewton = 0.01 newton.

1 newton accelerates a 1 kg mass at 1 m/s^2.

1 centinewton accelerates a 1 kg mass by 1 cm/s^2 = 0.01 m/s^2.

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**[quote=“Darkstorm1997, post:1, topic:316861, full:true”]
Hey, I have been wondering what is the units of AddForce function?
By units I do not mean the parameters - FVector. I mean the physical units. Is it in newtons?

I need this because I have an arrow which has a target. I want the arrow to get shot and get to the target.
I did not find any material on this so I have been thinking to use physics and use AddForce function. So the question is does AddForce’s units is newtons?
[/quote]

**

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I don’t understand why you’re requoting the question

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Sorry to necro an old post, but thank you for clarifying this.

I am a total newbie (5 days so far! but I do come from Unity with few years of exp.) to UE so I wanted to leave this here so someone like me can benefit in the future.

You can actually test this out in the editor with below.

Mass x Gravity x 100 = Force required to hover.

image
image1355×360 59.3 KB

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What is your pawn’s mass? I have tested this too and the AddForce() method seems to me to require the Acceleration (in cm/s/s), NOT force (in Newtons). Multiplying the AddForce() first parameter by mass makes by pawn go ridiculous speeds, assuming its Acceleration * Mass (which is Force in Newtons, times 100 for Unreal Units).

I have tested with different masses, using acceleration as the first param makes them all go down at the same speed, whereas using force as the first param (Accel * Mass) makes them go at much higher speeds than I expect.

If your mass is 1 kg in the example you illustrate, that would result in the expected behavior, but it seems based on my testing any other number results in unexpected behavior.