I'm trying to create an HDA that will do some RBD destruction of Unreal assets in Houdini using the Labs Vertex Animation Textures node and the RBD Material Fracture node. When I render the VAT node on a simple torus in Houdini it works fine - I get the textures, materials and fbx files. When I install the HDA in Unreal and try to Initialize for Engine and then Render the VAT, it does not work. I get an fbx and I get the _pos.exr texture. I do not get a materials folder or the _rot.exr texture.
I tried exporting the geo from Unreal as .fbx. When I import that .fbx into Houdini the verts are scrambled, as if the vert count is wrong. It's not 100% scrambled, but it's wrong. The cook log suggests that some attributes that Houdini wants are missing, e.g. name. The FBX includes various LODs.
I am using UE 4.26.1 and Houdini 18.5.408. I'm using version 2 of the Engine plugin.
Any ideas?
I have a very simple network that accepts geo from the HDA in Unreal, via the Object Merge. I put the Labs VAT node inside a ROPNet so that it can be included in the HDA definition. I can not get the _rot.exr or the material .json. I do not know why it is not working.
In the HDA I have exposed the Initialize for Engine button and the Render button that is on the Labs VAT node, so I can click those buttons from within Unreal.
Edit: One thing that seemed to help was to go into the type properties, and in the Save tab, turn on the option for Unlock New Nodes on Creation.
In order to be able to click on a button in a HDA, the node that holds the button needs to be unlock.
What that means, is that generally, you want to add the node that has the exposed button to the HDA's "editable nodes". This will ensure that when the HDA is created, those nodes are unlocked, and their buttons can be pressed.
In your case, you want to add the Labs VAT Node as an editable node in your HDA's type properties.
Thanks for the tip! I put the name of the node I want to click a button on into the Type Properties -> Node -> Editable Nodes text field, but it only works in Unreal if the HDA in Unreal has the Cook Triggers -> On Parameter/Input Change button checked on. Can I set it up so that I can use my HDA button without having that box checked? It's super slow and annoying having it recook every time I change a setting.
I tried adding a python callback to render the VAT node. The line of python works in Houdini, but it seems like it's not getting run from Unreal.
