Best approach for climbing between vertical tiles in layered tile-based world (Recast Graph)

General
1

Hi Aron,

I’m working on a side-view game using a 3D tile grid (grid[x, y, z]) to represent terrain. Each tile is either walkable (Dug) or solid (Soil). I’m using the Recast Graph with A Pro*, and normal ground movement (on z = 0) works great.

:wrench: Challenge

I want agents to climb vertically in two situations:

  • Up/down (Y axis) — to dig tunnels vertically (e.g. digging into a ceiling or dropping into a shaft)
  • Forward/backward (Z axis) — when digging into multi-layered rooms (e.g. climbing from front wall into deeper z+1, z+2)

:earth_africa: World Structure

  • All tunnels exist on z = 0 and are walked left/right normally
  • Some rooms go deeper into Z (from z = 0 to z = 3, etc.)
  • A tile is reachable only if it’s:
    • A Dug tile the agent can walk onto, or
    • A solid wall the agent can climb onto or climb down from

:brain: What I’m Considering

  • Using NodeLink2 to define transitions (up, down, or into deeper Z)
  • Dynamically creating/removing these links as the terrain is dug
  • Possibly using a custom TraversalProvider to handle special climbing logic

:question:My Questions

  1. What’s the best practice for enabling vertical climbing in this setup?
  2. Should I manually link climbable tiles using NodeLink2, or is there a better method?
  3. Is Recast Graph the best fit for this world structure, or would LayeredGridGraph give more flexibility for vertical transitions?

Thanks for any guidance — I’d love to keep using A* Pro for this system if vertical climbing can be integrated cleanly!

2

Hi there, I’m trying to wrap my ahead around the concept. It sounds like, since it’s sideview, that the view will be perpendicular to the X axis and move left and right for movement, back and forward for rooms for digging “out/in” and digging up and down on Y-- if that’s not right let me know! Ideally with a screenshot lol

Let me ask this; what’s the usecase for Astar in the first place? Is the player movement controlled through Astar and not directly with left/right/up/down inputs?

3

Hi, thanks for the follow-up!

Yes, your description is correct — the game is side-view, with:

  • X axis = left/right movement (normal walking)
  • Y axis = vertical climbing/dropping between tunnel levels
  • Z axis = going “into” or “out” of the screen for deeper rooms/caves

MovementConcept
MovementConcept1024×1024 37.4 KB

Use case for A*
The player doesn’t control dwarves directly with raw left/right/up/down inputs. Instead, they click to assign a dig/build/move task, and the dwarf AI finds its own path there automatically. That’s why I’m using A* Pro — it handles pathfinding around dug/undug terrain and ensures dwarves take valid, walkable routes.

Current status

  • Using Recast Graph.
  • Z-depth navigation already works fine — moving into and out of deeper rooms is handled perfectly.
  • The only challenge is vertical movement along the Y axis (e.g., climbing a 1–3 tile shaft or dropping down).

The problem
Recast Graph can’t detect new vertical connections when the world changes unless I pre-place NodeLink2 objects — but since my terrain is fully destructible, dwarves can dig anywhere, so links must be created/removed dynamically at runtime as tunnels open up.

Main question
What’s the best way to allow dynamic Y-axis transitions (up/down climbing) in a destructible environment using the Recast Graph? Is there a built-in method to detect and create those links on the fly, or do I need to implement my own runtime NodeLink2 placement logic?

Thanks!

4

Honestly this may be a good use case for Point Graphs rather than Recast graphs. You can place nodes for it within your individual “cubes”.