Hi,

In Houdini, I have created a basic heightfield. I have also used the copy-to-points node, with the "Pack and Instance" option selected, in order to instance trees across the heightfield.

Now within Unreal Engine, I would like to be able to swap out the mesh that is being instanced. This process is demonstrated in this official Houdini tutorial video: https://www.youtube.com/watch?v=SI_kkmdeMsw&list=PLXNFA1EysfYlywjFsSG0rdhY1pGjYjQvK&index=7 [www.youtube.com]

However, I do not have the option to replace the instanced mesh in Unreal:


If I try to replace it with another mesh, then it simply doesn't allow me to overwrite the default mesh:


Any help would be much appreciated.

Hi,

That is expected as we've deprecated this workflow in Houdini 20.5:
https://www.sidefx.com/docs/houdini20.5/unreal/instancing.html#overriding-deprecated [www.sidefx.com]

Now, you can still use it in 20.5, but need to re-enable it in the plugin settings.
This, however, won't be possible in future versions of Houdini.

What this feature did, was give you the ability to change the instances on the output of the HDA - but if you had multiple variations (ie, replace the blue cone with 3 different tree meshes) then the plugin would randomly assign the variations, with you having no control on the assignment.

Replacement workflow for this would be:
- use geometry inputa, with "export as reference" enabled (since you don't want the full mesh data - just the path to the mesh)
You can then assign the input's points to your instances and get a similar result.
Replacing one of the input mesh will swap the instances as expected.
- You could use string params, as drag and dropping a uasset will extract its path - and then assign that parameter value to the instance point.
You can even set the string param to display as an asset picker by using the "unreal_ref" tag on the param.
see: https://www.sidefx.com/docs/houdini20.5/unreal/parameters.html#strings [www.sidefx.com]