Unreal 4.20 NavigationSystem changes

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#1

I’m doing the course in 4.20 and ran into the issue of ProjectPointToNavigation() not working. Error says it is not a member of UNavigationSystemBase.

After a few days of searching I found out that most Navigation System-related code has been moved out of the Engine code and into a new Navigation System Module.

So to get the code working I had to add “NavigationSystem” to the core modules in build.cs:

PublicDependencyModuleNames.AddRange(new string[] { “Core”, “CoreUObject”, “Engine”, “InputCore”, “NavigationSystem” });

In .h change: “AI/Navigation/NavigationSystem.h” to “NavigationSystem.h”

in .cpp change:

bool bOnNavMesh = GetWorld()->GetNavigationSystem()->ProjectPointToNavigation(HitResult.Location, NavLocation, TeleportProjectionExtent);

to:

UNavigationSystemV1* NavSystem = FNavigationSystem::GetCurrent(GetWorld());

bool bOnNavMesh = NavSystem->ProjectPointToNavigation(HitResult.Location, NavLocation, TeleportProjectionExtent);

Hope this helps someone

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#2

Thanks for this info, although it doesn’t work for me. I updated to the latest version before starting this course, 4.2.3, and I get the errors;

“FNavigationSystem::GetCurrent’: no matching overloaded function found”
“TNavSys *FNavigationSystem::GetCurrent(UWorld *)’: could not deduce template argument for 'TNavSys”

#3

I have it working now. I added

PublicDependencyModuleNames.AddRange(new string[] { “Core”, “CoreUObject”, “Engine”, “InputCore”, “NavigationSystem” });

to the wrong build.cs file. Because this was the navigation system I added it to the navigation build file instead of the main one.

1 Like
#4

I still get the errors

Severity Code Description Project File Line Suppression State
Error C2672 ‘FNavigationSystem::GetCurrent’: no matching overloaded function found ArchitectureExplorer D:\Unreal Projects\Udemy_VR\ArchitectureExplorer\Source\ArchitectureExplorer\VRCharacter.cpp 58

Severity Code Description Project File Line Suppression State
Error C2783 ‘TNavSys *FNavigationSystem::GetCurrent(UWorld *)’: could not deduce template argument for ‘TNavSys’ ArchitectureExplorer D:\Unreal Projects\Udemy_VR\ArchitectureExplorer\Source\ArchitectureExplorer\VRCharacter.cpp 58

After making these changes. Any further ideas?

#5

Hi, besides adding the module I got it work by casting to UNavigationSystemV1. Hope it helps.

UNavigationSystemV1* NavSystem = Cast<UNavigationSystemV1>(GetWorld()->GetNavigationSystem());
bool bHitNav = false;
if (NavSystem != nullptr) {
	bHitNav = NavSystem->ProjectPointToNavigation
		(
			OutHit.Location,
			OutLocation,
			Extent
		);
}
1 Like
#6

I am getting “unresolved external symbol” errors when trying the UNavigationSystemV1 approach. I included NavigationSystem.h. I am using UE4.21.2

Error LNK2019 unresolved external symbol “__declspec(dllimport) private: static class UClass * __cdecl UNavigationSystemV1::GetPrivateStaticClass(void)” (_imp?GetPrivateStaticClass@UNavigationSystemV1@@CAPEAVUClass@@XZ) referenced in function “private: void __cdecl AVRCharacter::UpdateDestinationMarker(void)” (?UpdateDestinationMarker@AVRCharacter@@AEAAXXZ) ArchitectureExplorer E:\UE4 Projects\ArchitectureExplorer\Intermediate\ProjectFiles\VRCharacter.cpp.obj 1

#7

I got it working.

DONT copy and paste…
PublicDependencyModuleNames.AddRange(new string { “Core”, “CoreUObject”, “Engine”, “InputCore”, “NavigationSystem” });
…
From the post above. Just type it in. The quotation marks are not the same as the standard quotation marks.

#8

Help,
I’m working with UE 4.22 and have just started the course and have just arrived at point 13. Projection on the navmesh. VS does not compile anymore, “UNavigationSystem :: ProjectPointToNavigation is Deprecated”
Where do I have to make changes compiling VS? Please step by step if possible.

#9

Epic provided a python (3.5) script that will output the needed changes
https://epicgames.ent.box.com/s/537wc3x95udak7uqq8wja19fyvbgz7ck
Just put that into your root project directory and run it.

#10

How is that meant? what does the python 3.5 script do? does this have something to do with my problem?

#11

The navigation system was changed in 4.20 running that script should tell you what changes you need to make to update to the new API.

#12

My understanding is, Unreal uses Python 2.7 by default. Can you give me a little more help - where do I put the script exactly - in the project folder at the top, and where do I start the script? do I then open the project or VS?

#13

It’s a separate thing. Install Phyton 3.5 or above on your system. Download that file and put it in the root of your project and then run the script.

Change MAKE_CHANGES_IN_SOURCE_FILES to true in the script if you want it to apply the changes otherwise it’ll do exactly what it says in that comment.

#14

I’ve been doing interim - copy in projectfolder-change MAKE_CHANGES_IN_SOURCE_FILES to true and save - right mousebutton - open with python 3.7 - then open my project - no effect

#15

Do you not get any output with that as false then?

#16

no, no effect.

#17

Also what errors did you get? Not sure if that script adds “NavigationSystem” to the build.cs which you need to do.

#18

Can I find the build.cs when opening via Unreal Engine in VS? Where?
Then copy paste NavSysPathsUpdate.py?

#19

It’s in your Source directory.

Also you haven’t said what errors you got. You should also check the Q&A there’s a couple posts regarding this

#20

image

I think I have to replace the VRCharacter.ccp and the VRCharacter.h in VS with an updated UE.4.22 syntax regarding #include “AI / Navigation / NavigationSystem.h” and bool bOnNavMesh = GetWorld () -> GetNavigationSystem () -> ProjectPointToNavigation (HitResult.Location, NavLocation, TeleportProjectionExtent);
Does anyone already have a UE 4.22 solution for this?

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