How to change navigation cost in realtime

Development World Creation
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1

In our game, the player builds roads (these are square tile pieces). I am looking for a way to make the ai prefer to walk on roads if possible.

The only method I’ve seen so far is to use a NavMeshModifier volume, but I haven’t been successful in spawning one at runtime.

Is there a suggested method of handling realtime navigation cost changes? (Either in c++ or blueprint)

Thanks in advance

2

Rama is making great dynamic AI system

, pm him

3

Thanks Tim, that looks like a really great system but unfortunately Rama re-invented his own system entirely, I simply need to modify the navigation cost (I imagine this should be possible with the existing navmesh system).

4

Well, you can ask him what’s the best wy to implement it in your case.

5

#Solution

  • Make a BP of NavArea_Default

  • Set the custom cost value as seen in picture!

  • Make a c++ class that extends the nav modifier volume

  • Set its mobility to moveable in the constructor!

  • You should now be able to spawn it at runtime, position and resize it!

    UCLASS(hidecategories=(Navigation, “AI|Navigation”))
    class ANavModifierVolume : public AVolume, public INavRelevantActorInterface

extend the above

in the C++ constructor

RootComponent->SetMobility(EComponentMobility::Movable);

14425-navbp.jpg
14425-navbp.jpg828×295 28.8 KB

1 Like
6

Thanks Rama, this looks like what I’m after.

I’m having a problem extending from ANavModifierVolume though, I’m getting many linker errors (here’s a sample):

error LNK2001: unresolved external symbol "public: virtual bool __cdecl ABrush::IsLevelBoundsRelevant(void)const " (?IsLevelBoundsRelevant@ABrush@@UEBA_NXZ)	...MobileNavModifierVolume.cpp.obj


error LNK2001: unresolved external symbol "public: virtual void __cdecl ABrush::CheckForErrors(void)" (?CheckForErrors@ABrush@@UEAAXXZ)	...MobileNavModifierVolume.cpp.obj

I’m running off of the launcher version 4.4.1 at the moment. Do you know of any steps to remedy this?

7

I am having the same problem. I’ve already spent a week trying t modify costs on runtime…How did you solve it?

8

For my purposes, the NavModifierComponent is what I am using

9

I tried to override cost functions in the nav mesh but I found that so *** difficult…Are you spawning NavModifiers on runtime and changing its costs?
Do you know if a lot of nav modifiers can bring performance issues?
Finally I would be very happi if you can you show me a sample code instanciating your own Nav Modifier.

Thanks!

10

I’m placing movable actors with NavModifierComponents attached to them. The components take a NavArea class that defines the custom costs