I’m doing a raycast in the Vector3.down direction.
It has no problem colliding with the object I want it to collide when I fall into the object along the Y axis.
When I try to run through the object at, say, along the Z axis, the Raycast will not hit the object.
Right. Nor should it. You are casting a ray down, so it will not hit anything that is not ‘down.’
Additionally, using Vector3.down will give you ‘down’ in world space, not local space. So if you rotated your object such that it’s feet were pointing away from the floor, the ray cast would still be pointing towards the floor.
Raycasts do not trigger if you start the ray from inside the object. I’m assuming your ray is starting from the centre of your character, so when you pass though another object the ray is beginning inside the objects collider and therefore not registering a hit.