I don't know if this is a BUG or Im doing something wrong but is driving me crazy and keeps me away from making progress in my project.

I made a very simple HDA that takes a mesh as input (Object merge), then, it computes the boundaries of that mesh and see how many times that mesh fits in a spline (line), resample the line and use a copy to points to instance. The problem is, that if I use the 'Pack and Instance' option in the copy to points node, UE4 crashes. If I disable the option, HE gives me a new mesh as output but I want an instanced mesh as output, not a new static mesh.

However, if I use the attribute method everything works fine but I really want and need to use the object merge node.

If I supply a default houdini Box into the copy to points method, the hda works fin and ue4 doesn't crash the main problem is the object merge node because Im trying to import a mesh from unreal.

I have read the documentation and seen some YT videos, and Im pretty sure this is a bug.

Currently using UE4.27, Houdini Engine v2 and Houdini 18.5.696

Tested the HDA in a new project inside UE5.0 EA2, the HDA works fine so this is very likely a bug with 4.27

Yeah, I'm fighting with the same - in my case it crashes if packed mesh has a material attribute (unreal_material on primitive or detail before packing). Also crashed when using unreal static mesh reference directly from Unreal (both ways - pack before input or packing inside HDA before copying to points). This was definately working before in older versions!

Houdini 19.0.455 + Unreal 4.27.2

I think this should be elevated to a very high priority - most Houdini Engine/Unreal workflows rely on instancing packed objects, so this kinda breaks almost everything!

Here is a simple test HDA attached if anyone wants to try.
By default it does not crash - you have to enable the checkbox "Enable Crash Scenario" to crash.
It demonstrates both ways of the crash:
1. If no static mesh is set in Instance Mesh parameter, it will use internally generated packed geometry (cube) with material attribute.
2. If you set a static mesh in Instance Mesh parameter it works, but as soon as you click "Pack before export" (or add pack node inside HDA - it does not matter), it will crash.

If "Enable Crash Scenario" is not checked - it will use plain packed geometry (sphere) without material attribute - and it works fine.

I'm using latest Unreal 4.27.2 and Houdini 19.0.455 (Crashes also in today's daily build 19.0.464).

For now the workaround is using attribute instancing using "unreal_instance" point attribute. This works fine, so something must be wrong with how copy_to_points is made into unreal instancer.

Facing this problem for year I guess. Still working on Houdini 18.5.532 - last version whitch works with instancing without crashes. Waiting to fix this problem a lot. How possible is many developers use this tool with such bug?