nicktron3000 said:
So now I'm confused. I was under the impression that all attacks have hitboxes (in most cases multiple), and that the strength and priority of the attack was a set numerical value inside those boxes.
This is how I understand it.
Every attack causes a hitbox to appear (except maybe DK's >100% ledge get-up attack) for some amount of time.
Every character has a hurtbox, which is the area where if a hitbox touches, they will be "hit." It's generally the character's body.
When an attack is "disjointed" or has "high priority," the hitbox of the attack extends farther than the character's hurtbox. Think of Link's sword-based attacks; they are disjointed because the hitbox of the sword extends outwords, but his hurtbox is still just his body. The opposite is when hitboxes do not extend from your hurtbox, such as Pika's f-air.
When two characters try to attack eachother, the game checks the collisions of hit/hurtboxes. If Pika tries to f-air Link while he is f-smashing, Link's f-smash will probably win. This is because Link's sword's hitbox overlaps with Pika's hurtbox before Pika's hitbox has the chance to make it all the way to Link's hurtbox, his body. Therefore the game registers Pika as being hit while Link is fine.
Attacks that are usually thought to be "high-priority" just have unreasonably large hitboxes. Kirby's uptilt's hitbox is so huge and his hurtbox is so small that not many attacks can reach his hurtbox before the attacker's own hurtbox comes into range of the uptilt.
As for clanking, I think what happens is when two ground hitboxes collide, a "clank" occurs. Otherwise, hitboxes ignore eachother. So if two air attacks (or air vs. ground) meet, the hitboxes pass through eachother. This can result in both characters registering as being hit if both hitboxes connect with their targets at the same time.