Capsule Cast

[ViachaslauBusel]

Hello, could you please explain how "Simulation.Sweep" works. On the example of a capsule.
Simulation.Sweep( new Capsule(radius, height), new RigidPose(origin + Vector3.UnitY * (height / 2.0f), Quaternion.Identity), new BodyVelocity(normalizedTargetDirection), targetDistance, map.BufferPool, ref handler);

public void OnHit(ref float maximumT, float t, in Vector3 hitLocation, in Vector3 hitNormal, CollidableReference collidable)
t - Is this distance?

here is an example of how it works in Unity

the red area is the collision detection area

[RossNordby]

t is the time to impact, given the input sweep velocity. For example, for a pure linear sweep, if the velocity has a magnitude of 2 and the t value is 0.5, then the distance traveled to the impact is 2 * 0.5 = 1.

The t value is used instead of distance because distance ceases to be the most useful output when a sweep has nonzero angular velocity. For ray casts or linear-only sweeps, the time of impact can also be used to multiply the ray direction or linear velocity to get displacement easily.

(As a side note, in bepuphysics2, capsules do not take a full 'height' in their constructor- instead, it takes the length of the internal line segment. A capsule with 0 length would just behave like a sphere.)