How to actually use A*?

[wowland856 (wowland)]

I am running into a problem with one of my pathfinding npcs, I want him to ignore doors when pathfinding so he isn’t stuck in one room until you find him, but every post I see about this says to just make your own pathfinding. I heard A* is the most efficient, and I have found a few examples, but how would I translate this to an npc? The ones I have found are very simple showcases of it and I wish I could find an example of an npc utilizing it. Can someone give me some resources(videos, wikis, books, etc) to point me in the right direction, as I feel like this is a bit out of scope for me to figure out for myself. I am not asking for you to write an advanced A* pathfinding npc for me, simply just to point me in the right direction.

[Katrist]

A* Pathfinding (E01: algorithm explanation)

Link to an implementation of it in Roblox:

How does A*Pathfinding Work

Here is my implementation if you need a reference. A*Pathfinding.rbxl (16.1 KB)

[dthecoolest]

The key for an NPC, is to translate it into 3D, the simplest way to do it is with a grid representing Vector 3 coordinates. And a custom built Get Neighboring cells function.

Learning the grid is an entire topic by itself one way to learn how to translate a 2d table grid into 3d coordinates is from terrain generation, there is an integer cell and it translates into vector 3.

gridData[1][1] = Vector3.new(0,0,0)
gridData[5][5] = Vector3.new(5,0,5)

From there you can traverse this 2d Grid using A star path finding from gridData[1][1] to gridData[5][5] and move an npc from vector3.new(0,0,0) to Vector3.new(5,0,5) using :MoveTo or tweening depends on what you want.

here are some more resources,

Red Blob Games: Introduction to A*

Pathfinding Algorithm Simulation

Hi Developers, Recently I have been exploring Artificial Intelligence and came across pathfinding algorithms. I decided to take this deeper and implement them inside of Roblox. It was a lot of fun to work with all these algorithms and see how they differed from each other. After implementing some algorithms, I turned it into a cool little game where you can visualize them and decided to open source it. I hope you can learn from it and even have a little fun with it too! Implemented Algorithms: …

[wowland856 (wowland)]

Thank you everyone for your responses, this is very helpful!

[BJCarpenter]

Yeah you can get the code from Wikipedia, nd also decide a way to define walkable and non-walkable nodes, plus Doors…

You could use a ray-caster, and include Doors in the Whitelist (The model itself:

You could turn that place into a 3D chessboard., and have Players drop bradcrumbs with info of Next Breadcrumb… This method would ignore Doors…

You could use Roblox Pathfinding but fix the Doors: Make them out of water… or somehow make them walkable to the Pathfind…

[Judgy_Oreo (phoenixwhitefire2000)]

@wowland856

I want him to ignore doors

You could use the new pathfinding modifiers for this, although it’s still in beta.

New Pathfinding Modifiers - Studio Beta

Hello AI developers, Currently, PathfindingService almost always returns just the shortest path between the source and the target points. However, the optimal path should often consider the character/agent abilities, terrain type and game rules. For example - you may want an NPC to travel over a bridge instead of swim through water, cross a street in the crosswalk, or avoid an area that would damage the character. Introducing PathfindingModifiers PathfindingModifiers are instances used to an…

[wowland856 (wowland)]

l was not aware of this, I will get on this right away! Thanks! I actually just made my npc find the nearest door when the patrol paths fail so it can’t get stuck, but this will be so much better!