Spherecast question

Unity Engine
1

I want to see if anything is X distance from the character and I was wondering if something like this would get the job done

Physics.SphereCast (transform.position, X, transform.forward, hit, 0);

Will that collide with anything inside the sphere? or will something completely inside the sphere not show up as a collision?

2

It should be fine to detect anything infront of the character, you will need to cast enough distance to account for the chracters next step though
If you are moving fast enough such that you would cross a distance of 2 units in the next step, but only cast a ray 1 unit then it could miss something