arkaland

Houdini 15
Create a box
Createa a PolyExtrude node

Select a face on the Z-Axis of the box for the PolyExtrude node as group
Set divisions to something higher than 1
Set Spine Shape to Curved
Enable Transform Extruded Front
Set Transform Space to Global

Now when you extrude it all looks correctly

But when instead of extruding on the Z-Axis, you extrude a face on the Y-Axis or X-Axis, it looks like this

ttvdsfx
2) Instance baking is definitely on our to-do list. We are still thinking about possible approaches for this. If you can think of a good approach do let us know. As far as I know, there's no instanced static mesh asset type in UE4. One way to bake instances would be to generate Blueprint with attached instanced static mesh component and embedded instancing/instanced mesh information.

… Can you please elaborate more on ‘Basically to just use point locations for item placement’ ? …

Thanks for the in depth response, I appreciate it.

Yes, I think the blueprint approach would work.

Here is a screenshot with two possible additions:



These are some of my unfiltered thoughts on mesh instancing and blueprints with the Houdini Engine in Unreal:

-The user presses a bake button in the new tab from the screenshot
-Instead of a static mesh added to the content browser, it adds a blueprint to the content browser.
-The blueprint consists of a root with instanced static mesh components
-The amount of these components is equal to the number of instanced inputs on the HDA

The setup described above could also be used to allow a third file input, the one marked in red for blueprint actors, as an input for the HDA.
Instead of adding an instance static mesh component, it would add the blueprint input as child actor components to the Houdini blueprint.
The user would have to act responsible for performance here because dragging in a blueprint with a point light and spawning 1000 point lights might be a bad idea.

Example that uses the different inputs and how it might result:
A single HDA to create a landscape with 1 geometry input for a castle, 1 instanced input for flowers and 1 blueprint input for point lights:
-The landscape gets created by using the HDA and Houdini engine with sops (grid > mountain sop etc.)
-The geometry input for the castle, which is a mesh already sitting in the Unreal content browser
-The instance input is used to place flowers on the landscape
-The blueprint input is used to place 10 blueprints with point light setups around the castle

The generated blueprint would have (I think) 14 components:
-a root component
-1 static mesh component (the landscape baked by Houdini)
-1 static mesh component (for the castle)
-1 instanced static mesh component (for the flowers)
-10 child actor components (for the blueprint inputs with lights in this case)

Maybe the user could have some freedom in deciding how the result should be organized by having the outputs separated,
but in theory it could result in a single blueprint.

But point lights is just one example. When blueprints can be used for inputs, entire gameplay events, post processing volumes, particle systems etc. could be
procedurally spread across the landscape this way with Houdini. A procedural building could now have scripted elevators by using blueprint inputs instead of just an elevator mesh.

Thanks for reading, I hope I was eloquent enough to convey some of my thoughts.
If there are some fatal flaws in my way of thinking about this or if it's all way out of scope, please let me know.

First of all I think this is a really powerful and well made tool with a lot of potential, thanks to all those who created it.

I hope my questions will be clear enough

1. If I have multiple materials on an object in Houdini, how do I get those recognized as multiple material slots in Unreal?

2. Is it possible to bake a HDA actor that is composed of instanced meshes and even keep or convert these instances as Unreal Engine instanced static meshes?

3. Is it possible to somehow keep the location of an object after baking it, or replace the HDA actor with the baked version at the same location?

4. Is it be possible to not only allow static meshes as file inputs, but blueprint actors as well? Basically to just use point locations for item placement, not to process the blueprint contents by Houdini (I think that would be impossible).

5. Will it ever be possible to use Houdini Engine at run time in shipped products? I think it would revolutionize procedural games.

Thanks for your time.