Dear community,

I am having trouble creating a simple HDA that takes input-geo (e.g. Unreal default cube) from an UE Level as an input to stencil window holes into a wall. Problem is the boolean operation doesn't get performed.

I have taken the following steps:

1. Created an Object Merge-SOP and exposed its top operator-path parameter to my HDA.
2. Added a Boolean-subtract-SOP and inputed the Object-Merge as Input B.
3. Imported the HDA into UE4 and chose “World Outliner Input” in the parameter's input type.
4. Created a default cube and moved its transform into the main geo (wall).
5. Assigned the cube in the World Outliner Input.
6. Recooked and Rebuild the asset.

The boolean works fine within Houdini via a dummy-box.

Does anybody know what I am doing wrong?

Best,
Nicolas

Unless I'm misunderstanding your setup, you need to provide the wall in which a hole will be cut as an input into Houdini as well.
Is this one of your world outliner inputs? You can't just provide the cutter to Houdini. It specifically needs both the cutter cube and target geo to be cut.

You could build a switch node where you check if there is a geometry with the line npoints(“”../object_merge3")> 0. Drag your dummy geo first into the imput and your object merge second. That means, you check if it has no geometry. If it doesn't and cannot perform a boolean, it does a boolean with the dummy instead.

There is a Video from Entagma at 3:11
https://www.youtube.com/watch?v=VX5S0c-V_jc [www.youtube.com]