doughCat Dec 26, 2011 at 5:25 AM Hi, I'm new to farseer, and i'm stuck on a simple problem: i have two fixtures colliding and i need to determine the normal impulse that results at the contact. Right now I have added an OnCollision event handler: ```mainBody.OnCollision += OnCollision; ``` ```private bool OnCollision(Fixture f1, Fixture f2, Contact contact) { // Figure out normal impulse between f1 and f2 :s return true; } ``` Is there a simple way to determine the impulse due to a collision? Any help would be great. Fredrik_ Dec 28, 2011 at 4:55 PM `You should be able to do this:` ``` Vector2 normal; FarseerPhysics.Common.FixedArray2 pointlist; contact.GetWorldManifold(out normal,out pointlist); ``` `Then the normal should be returned. ` doughCat Dec 28, 2011 at 7:51 PM Thanks a lot for the help Fredrik!  I see that that would return the normal between body A and body B. But I was looking for the normal impulse that results from the collision. I found this code in BreakableBody, its a PostSolve delegate: ``` private void PostSolve(Contact contact, ContactConstraint impulse) { if (!Broken) { if (Parts.Contains(contact.FixtureA) || Parts.Contains(contact.FixtureB)) { float maxImpulse = 0.0f; int count = contact.Manifold.PointCount; for (int i = 0; i < count; ++i) { maxImpulse = Math.Max(maxImpulse, impulse.Points[i].NormalImpulse); } if (maxImpulse > Strength) { // Flag the body for breaking. _break = true; } } } } ``` I will be using something similar.