Hi,

I'm using Houdini Engine to created instance based trees in UE4.
What I mean is that branches and flowers are instances of the same meshes.

The problem I have when I open the tree (which looks good in Houdini) in UE4 the instances look a bit off.
It seems to me that it just rotations are a bit off because flowers pivots seem to be in place.

At the attachment you can see a blue tree which was merged into a single mesh and looks correct.
But the red one which is built using instances is misaligned.


In Houdini however both of them look fine.


I'm using Pack node with pivot set to origin and Copy to Points node to generate the tree.
I've tried to set pivot point to centroid but still getting the same result.

Is this a bug or am I doing something wrong?
I would assume if this would be a bug with instance rotation somebody would notice it by now.

Appreciate your help!

I've found what HE to UE4 doesn't like and have found a workaround.

To get the tree I was copying packed flowers onto the branch and then copying the branch with flowers to points with NON-uniform scale attribute applied which is ok with Houdini but the engine seems to misinterpret this kind of transformation.
It works just fine with translations and uniform scale though. So the lesson here - don't apply non-uniform scale after instancing.

So my workaround was to try to avoid any transformations after instancing so I would apply all the transformations and attributes to the points only and then would copy branches and flowers to appropriate points at the end and it works fine now.

I still think that there should not be a problem in an ideal Houdini world so I've filed a bug report for this.

Good talk!

I've got pretty similar problem: instances in Unreal do not pick up the points' normals for orientation. Haven't found the solution yet (