Instanced Static Mesh Component not rendering when instances are added through C++ [RESOLVED]

Development Programming & Scripting C++
1

(Oops, made it a topic instead of a question)

After refactoring a bit of code to work with a few global Instanced Static Mesh Components instead of spawning/destroying static mesh components, i’ve run into an issue.

I can’t see my mesh instances!

Their collision is there, they’re in the Instances array and they’re being updated properly (I call UpdateInstance on them every frame to move them around), I can see them with Visibility Collision and Player Collision in the editor, but in game view, I cannot see them. Here’s how I add the Instanced mesh components (in BeginPlay):

InstancedItemMeshes.Reserve(Resources.Num());
for (const FResourceInfo& Res : Resources)
{
	UInstancedStaticMeshComponent* Comp = Cast<UInstancedStaticMeshComponent>(AddComponentByClass(UInstancedStaticMeshComponent::StaticClass(), false, FTransform(), false));
	Comp->SetMobility(EComponentMobility::Movable);
	Comp->AttachToComponent(GetRootComponent(), FAttachmentTransformRules::SnapToTargetNotIncludingScale);
	Comp->SetStaticMesh(Res.BeltMesh);
	Comp->SetMaterial(0, Res.BeltMesh->GetMaterial(0));
	InstancedItemMeshes.Add(Comp);
}

Here, Res is a custom struct that holds some information I need.

And here’s how I add the instances:

IT.MeshInstanceId = IT.GetMeshComponent(GameState)->AddInstance(FTransform(), true);

And finally, here’s how I update them:

MeshComp->UpdateInstanceTransform(Item.MeshInstanceId, FTransform(NewWorldRot, NewWorldPos), true, true, true);
MeshComp->MarkRenderStateDirty();

Here Item is also a custom struct that holds some information relevant to the system this is apart of.

(See my previous post about this project for some more context, if needed.)

2

Hi - I saw your original post about using SMs first - I agree that ISMs are a more optimal solution and a singleton instance manager is the way to go.

Is it possible your materials don’t have the “use with instanced static meshes” usage flag set?

3

Oh! I forgot to mention that. Yes, they do have that check set.

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(I even manually set the material of the component in the code, thought that may have been the issue, but no, it was not.)

EDIT: Perhaps it’s also worth mentioning that the Instanced Static Mesh Components are attached to and created by the GameState actor?

4

I’m not sure the GameState will work for containing those components - you could test by adding a simple mesh component to it as well to see if that renders.

I add a single actor to the level as my singleton - it’s in the world and in the actor arrays so is always in the correct render queues.

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5

Oh. Huh. That’s interesting, adding a static mesh component to the gamestate leads to the exact same behaviour. So I wasn’t doing anything wrong, I was just doing it in the wrong place.

I’ll try putting it on a seperate actor and I’ll mark as solution if that works. Thanks a ton!

EDIT: oh wait, right, i forgot to make it a question topic. I’ll rename it instead then. :joy:

1 Like