# Detecting sudden changes in velocity?

 0 I'm working on a racing game where the vehicle is normally colliding with pretty much anything/everything in the level (ground, walls, jumps, etc). So I can't use normal collision detection methods to check if the vehicle has actually "crashed" and not safely glanced off of something. I think the solution is to check for sudden changes in velocity, but I'm not sure how to do it. I'd like to check if the velocity falls below a specific minimum within a specific amount of time. Any ideas? more ▼ asked Mar 03 '10 at 01:13 AM rocket5tim 859 ● 12 ● 17 ● 33 I would also like to see a answer to this, as i would like to be able to know how to implement fall damage in a FPS i am working on. i.e I want it so that if i fall off a house, it wont kill me just take away some health,as this is closely related i have commented instead of asking my own question. Mar 03 '10 at 01:35 AM xToxicInferno For falling damage in a FPS game, see http://www.unifycommunity.com/wiki/index.php?title=FPSWalkerEnhanced I'd say this is a quite different question, since in a FPS game you can stop instantaneously and you don't care; it's only the falling distance you care about. Mar 03 '10 at 01:57 AM Eric5h5 add new comment (comments are locked) 10|3000 characters needed characters left ▼ Viewable by all users

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 0 You could compare the magnitude of the velocity of the previous frame with the magnitude of the velocity of the current frame (or rather, the sqrMagnitude, which is faster): ``````private var oldVelocity : float; var crashThreshold = 10.0; function Start () { oldVelocity = rigidbody.velocity.sqrMagnitude; crashThreshold *= crashThreshold; // So it works with sqrMagnitude } function FixedUpdate () { if (oldVelocity - rigidbody.velocity.sqrMagnitude > crashThreshold) { // Crash } oldVelocity = rigidbody.velocity.sqrMagnitude; } `````` more ▼ answered Mar 03 '10 at 01:52 AM Eric5h5 80.3k ● 42 ● 132 ● 521 Thanks, Eric. Works great so far in my initial tests. I had to tweak the crashThreshhold up to 50 for my particular setup. Mar 03 '10 at 11:07 PM rocket5tim add new comment (comments are locked) 10|3000 characters needed characters left ▼ Viewable by all users

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asked: Mar 03 '10 at 01:13 AM

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Last Updated: Mar 03 '10 at 01:13 AM