How to snap a point to the height of the navmesh surface?

Question

I'm making generator for EQS and need to put points on navmeshes located on different heights, one above other. So, my idea is to make raycast vertically and find intersection points with navmeshes. But how to do it?

I tried to set CollisionResponseChannel to NavMeshBoundsVolume but all raycast hits happened on the edge of volume's box, not on navmesh.

Answer 1

I found the function what does exactly what I need:

bool ARecastNavMesh::ProjectPointMulti(const FVector& Point, TArray<FNavLocation>& OutLocations, const FVector& Extent,
    float MinZ, float MaxZ, FSharedConstNavQueryFilter Filter, const UObject* QueryOwner) const

There is the example of usage:

void UEnvQueryGenerator_VolumetricGrid::NavigationRaycast(TArray<FNavLocation>& Points, const FVector& Position, FEnvQueryInstance& QueryInstance) const
{
    const UObject* Querier = QueryInstance.Owner.Get();

    const ANavigationData* NavData = nullptr;
    NavData = FEQSHelpers::FindNavigationDataForQuery(QueryInstance);

    const ARecastNavMesh* NavMeshData = Cast<const ARecastNavMesh>(NavData);
    if (NavMeshData == nullptr || Querier == nullptr)
    {
        return;
    }

    FSharedConstNavQueryFilter NavigationFilter = UNavigationQueryFilter::GetQueryFilter(*NavData, Querier, ProjectionData.NavigationFilter);

    TArray<FNavLocation> HitLocations;
    const FVector ProjectionExtent(ProjectionData.ExtentX, ProjectionData.ExtentX, (ProjectionData.ProjectDown + ProjectionData.ProjectUp) / 2);
    
    NavMeshData->ProjectPointMulti(Position, HitLocations, ProjectionExtent, Position.Z - ProjectionData.ProjectDown, Position.Z + ProjectionData.ProjectUp, NavigationFilter, Querier);
    
    for (int32 HitIdx = 0; HitIdx < HitLocations.Num(); HitIdx++)
    {
        Points.Add(HitLocations[HitIdx]);
    }
}