How Did That Miss? How Hitboxes Decide What Really Happens in Fighting Games

Hitboxes and hurtboxes! This is something of a follow-up to a previous video: Solving Problems with Frame Data. In fighting games, frame data is to time as hitboxes are to space. Together, they form the technical underpinnings that decide how fighting games interactions play out. Sometimes I use these blog posts as a way to introduce a video, but I’m going to use this one to expand on it instead, so it’s probably best to watch before continuing!

In the video, I stayed focused and talked exclusively about two kinds of (hit)boxes: hitboxes and hurtboxes. These dictate if and when hits actually land. If Balrog does a punch, it will momentarily create a hitbox that roughly corresponds with the location of his outstretched fist. If that box ever intersects the opponent’s hurtbox (which is usually roughly on top of their sprite/character model), the opponent gets hit. In this post, I wanted to at least briefly touch on the fact that there’s more out there than just hitboxes and hurtboxes.

Collision Boxes

If you look at a screenshot of Street Fighter V with the hitbox viewer enabled, you can see that there are more than hitboxes and hurtboxes. The green outlines show the characters’ hurtboxes. Inside those green outlines, there’s a blue outline filled with a semi-transparent yellow. This is called a collision box. The collision box governs whether one character can move through the other. For example, if you walk forward, once your character’s collision box touches the opponent’s, you’ll begin pushing them backward. When you see strange instances of characters passing through one another, it’s probably because one or both of the characters' collision boxes were either shrunken or absent.

Proximity Boxes

When you do a move in SFV, even before it can actually connect, it will force the opposing character into a block animation if they’re holding backward. This is called proximity guard. In the SFV hitbox viewer, the range at which a move will cause proximity guard shows as a yellow rectangle with no outline that extends along with the move. When this box intersects with the opponent’s hurtbox, they can no longer walk backward and the block animation begins. For this interaction specifically, the interaction triggers if the proximity guard box and the opponent hurtbox intersect on the x axis, even if the boxes don’t literally overlap.

If you imagine the hurtbox extended all the way to the top of the screen like a column, it’s easier to understand what I mean. These don’t have a widely accepted “correct” name, but since they’re boxes that trigger proximity guard, calling them proximity boxes seems pretty reasonable!

Conclusion

Some of these boxes won’t exist in every game. Many games don’t have proximity guard, so they have no need for proximity boxes. Some games might assign unique types of boxes to projectiles or armored moves. Whether you’re talking collision boxes, proximity boxes, or (insert thing here) boxes, the concept is still the same—they’re all just instances of geometric shapes governing how interactions play out behind the scenes. It’s fine to ignore all of them (and you can safely do so and be a great player!), but depending on your learning style, diving deeper into the world of hitboxes can help take your game to the next level. If nothing else, it’s fun to learn and understand what’s really going on under the hood.