The new puzzle in Sombionic I’m working on introduces a climbing mechanic and more specifically a ladder climbing. Implementing this turned out to be more complex than expected and took around 5 days to complete.
Melany can now mount ladders from both the bottom and the top. By approaching a ladder and pressing “E”, she will automatically move into position before jumping and grabbing onto the ladder.
The same interaction also works from the top of the ladder.
Melany can climb both up and down while dynamically switching her leading leg to keep the movement looking more natural.
The system also supports jumping off ladders, as well as grabbing onto them while airborne. Reaching the top of a ladder allows Melany to vault onto the surface by pressing “W”.
The main reason this system took so long to complete was due to mathematical issues caused by floating-point precision. When small positional values continuously stack over time, even tiny inaccuracies can become noticeable especially in a system like ladder climbing where every rung is evenly spaced and Melany’s hands need to align very precisely to avoid clipping through the ladder.
The system worked fine with ladders containing 10–15 steps, but I wanted to ensure it would remain stable even on extremely tall ladders with 100+ steps. The biggest challenge came from Unity’s root motion system... During looping animations the engine reconstructs root motion over time, which can introduce small floating-point accumulation errors. This caused the character to slowly drift upward or downward depending on the climbing direction.
After a lot of testing and debugging, I finally found a solution that fixes the issue and Melany snaps to the closest rung. The ladders now work correctly regardless of height, but realistically Sombionic will probably never feature a 100-step ladder, but I wanted the system to be reliable under any circumstance.
While working on the climbing mechanics, I also added the ability to climb onto objects and a free-climbing system, which will be expanded later in development. Free climbing is actually much easier to handle since it doesn’t require the same level of positional precision as ladder climbing.