Game Developer Explains Why Rollback Is Difficult in 3D Fighters

At this point, anyone who's even remotely interested in the online functionality of their favorite fighting games, has likely learned a fair share of things about how rollback works. To a point where even who aren't good with tech terms and anything of the sort can still understand explanations from people like Infil or Keits.

However, 3D games (let's just say it, Tekken) still remain a hot topic within this discourse. People know how smooth proper rollback feels, and they want to see this in their favorite 3D fighter.

Well, recently an indie game developer working on Gemion Function chimed in with perhaps the most easy to understand explanation for the issues that games like Tekken, Virtua Fighter, and SoulCalibur face when they attempt to implement better netcode.

The somewhat obvious part in all of this is that adding a whole different dimension makes things a lot more complicated. But what's not so obvious is that there is a solution, and it's to handle hitboxes the same way 2D games do.

That doesn't mean switching to flat boxes, but rather not having hitboxes that are tied to animations, which drastically increases the number of necessary calculations in a way that limits what rollback can do.

The video does an excellent job of demonstrating the difference between the two approaches, but as some have commented, the solution might not actually be as dauntingly difficult as the video suggests.

While changing existing systems is prohibitively costly and time-consuming, if the game is designed from the start to handle hitboxes within the code and character states, we could see a P2P fighting game with smooth rollback netcode.

It's likely that we haven't seen this done with the current behemoths (again, mostly just Tekken), because these series rely so much on carrying over the foundational elements of previous games to aid in the development process.

However, one potential upside here is that the gaps between titles become longer and longer. It sort of sucks for the fans, but it also means that each new title has to be bulletproof and stand the test of time. They need to be games that people can play for years. They need to be games that can handle constant changes and updates, which means that there are more and more reasons to give them the strong foundation.

Here's hoping that the new Virtua Fighter serves as a breakthrough example of what 3D fighting game netcode can achieve when done right.