Instanced Static Mesh doesn't rotate on instanciation

Development Programming & Scripting
1

Hey guys ! I’m currently doing real time growing trees, and i’m using an instanced static mesh component for the foliage, since every leaf is unique. When I add an leaf instance to my component, I put a random rotation on it. But for some reason, this rotation is not set, all my leaves have a zerorotator. The scale is set, the transform too, but not the rotation.

Here is the code :

//Instanced static mesh component instanciation, as a component of the tree
foliage = NewObject<UInstancedStaticMeshComponent>(this);
foliage->SetWorldLocation(GetActorLocation());
foliage->RegisterComponent();
foliage->SetStaticMesh(data->leaves[treeType]);
foliage->SetFlags(RF_Transactional);
this->AddInstanceComponent(foliage);

//Adding a instance of foliage
const FTransform leafTrans = FTransform(
FMath::VRandCone(normals[branches[i].segments[j].firstVertice + 2], 2.0f).Rotation(),
vertices[branches[i].segments[j].firstVertice + 2], FVector::ZeroVector);

foliage->AddInstance(leafTrans);

I recently changed the Instanced Static Mesh Component, I beggined to put it on a child actor, and the rotation worked. But I had to remove it for an other issue.

I’m sure it’s a small thing I’m missing, but I’m losing too much time searching on the internet, and there is not that much documentation on this subject…

Thanks :slight_smile:

2

What’s the relation between leafTrans and leafTrans2?

May be better do some test on your Transform. Like this:

for (auto i = 1; i < 100; i++)
{
	FTransform T;
	T.SetLocation({ i * 300.f, 0.f, 0.f});
	T.SetRotation(FQuat::MakeFromEuler({0.f, 0.f, 30.f * i }));
	foliage->AddInstance(T);
}

What does your tree look like now?

3

Oops, I made a mistake while copying my code. I add two leaf at once, so I instanciate two Transform, that’s why I got a “leafTrans2”.
Thanks for answering, I’ll try your test.

4

Ok, the problem was the scaling. For some reason, when it is set to zero, it also set the rotation to zero… Thanks for J0000J, I could put the finger on this issue. Thanks dude !