Have you tried making the curve node as editable? Check out the Curve Decorator HDA for an example. It can be found under Houdini install location/enigne/unity/Assets/OTLs/Samples/

The best way to do that is to provide a collider (e.g. plane) to the Target field in the Curve gameobject's UI.

Actually you asked for snapping. Currently not possible with the curve editor, but I'll add it as an RFE.

The reason the material assignment is lost is because the plugin is regenerating the output but isn't aware of how to handle overrides.

One way to “keep” the material is to have its file path be set as a string-based primitive attribute in the HDA. Give the attribute the name of “unity_material”. The path should be relative to the Assets/ folder. (e.g. unity_material attribute with value “Assets/Materials/testmat.mat”).

Another way would be to specify a “unity_script” detail attribute which calls an existing script in your Unity project to re-assign the material. This allows to do more general post-cook setup as well.

I believe your question has been answered through our support, but for anyone else looking for similar answers:

1. If the other company will not be creating assets in Houdini, but would still like to modify (cook) assets in Unity (or game engines), then yes, they only need the Houdini Engine license.

2. No, the EULA does not allow mixing licenses for the same assets. So if you create HDAs with Indie, you can't use commercial license to work with it.

3. Once the HDAs have been cooked and saved in a Unity scene, then they can be used as is without a Houdini Engine license as long as they don't need to be recooked (modified) via Houdini. Now if you want to keep it clean and ensure that the other artists are not tempted to mess around with the HDAs, one way to ensure this would be to have a “work” scene where you work with the HDAs, then bake out to a prefab, and instantiate the prefabs in the real scenes. If you ever need to update those prefabs, you can bake out to a new prefab, then just drag & drop onto the previous prefab. It should update the instances.
Note that you still need to have the plugin folders (Houdini/, HoudiniApi/) checked into SVN (including the .meta files). Currently the baked prefabs still use the Houdini plugin scripts, hence the requirement to check in the plugin folders into source control.

4. If you mean build systems like nightly builds, then no, they don't need a license as long as they are not cooking or modifying the HDAs to regenerate through Houdini.

We don't allow mixing of Indie and Commercial licenses on the same machine. Please email support@sidefx.com to help you setup your license.

So that would be sending height data upstream to Houdini from Unity. Currently not possible, but is part of future plans to add in.

A workaround (haven't tried it myself) would be to use the Export Raw functionality in Unity Terrain settings. You might be able to use that exported file as input (heighfield) for your HDA.

Another method would be write a script that can query the height values from the terrain data (https://docs.unity3d.com/ScriptReference/TerrainData.GetHeights.html) and somehow marshall into your HDA as a parameter input (as float array or file data). It can be a little tricky to get the size and coordinates to match up though.

Currently the Unity plugin does not directly support Houdini heightfields as Unity terrain. As a workaround, use a convert_heightfield, which will then allow the plugin to bring it in as a regular mesh.

There is development currently being done to support heightfields directly. As for ETA, the best I could promise is sometime this year.

This looks amazing. Love the atmosphere, and visual style. Making of video is pretty cool as well. I sent you a PM.

You'll have to create primitive groups, then assign a material for each group. In Unity, you might have to turn off Split Geos by Group under the Cooking tab on the asset's Inspector UI.

See this video that shows setting multiple materials via primitive groups:
https://youtu.be/zzcBhuRLJZo?t=109 [youtu.be]

You're welcome. It has been fixed, and should be available in tomorrow's build.

Yes, there seems to be a bug with the mapping of the painted values when transferring back into Houdini. Will update this thread once it has been fixed.

Thanks for posting this. Which Houdini version and macOS did this problem occur on? Thanks.

Actually it should work if you make sure to start with Assets/

Ziboo
Thank you for the detail answer

seelanv
If they do need to modify the parameters to generate different output, then yes, they will need to have it installed or access to it via network

Does that mean that a studio can only have 1 Houdini Engine licence on a remote computer that every Unity User will hook via network ? Doing so they can modify parameters in Unity ?

Sorry I tried to find detail information on that but couldn't find it…

Technically it is possible, but please follow up with your licensing/sales contact to make sure your usage falls within your licensing agreement.

What happens if you generate an FBX in Houdini with the same parameters and import into Unity?

Are you able to attach an HDA for me to test?

Ziboo
Will Houdini Engine support runtime one day ? soon ?

1. One day runtime support might be possible. But not soon. As you can imagine, there are licensing issues to sort out besides just the technical.

Ziboo
Will you support Instanced Indirect for instancing geometry on points for maximum performance ?

2. We'll have packed primitive and object instancing support (see this page http://www.sidefx.com/docs/hengine/_h_a_p_i__instancing.html). With object instancing, you can specify either Houdini object nodes or existing Unity gameobjects in the project.

Ziboo
Does every user of Unity needs Houdini installed on their machine ?

3. Depends. As long as the user is not manipulating the parameters of an HDA in Unity, there is no reason to have Houdini installed. They can work with the output gameobject data. If they do need to modify the parameters to generate different output, then yes, they will need to have it installed or access to it via network. Baking outputs allows you to strip away the Houdini Engine components and completely eliminate the need for it, so that is a way to ensure that they don't try to modify parameters. The updated version of the plugin will allow you to update previously baked out prefabs and existing baked out gameobjects (non-prefabs) so that you can have a workflow where the HDA and its outputs can be completely separate, but able to be re-linked when need to update. And this update can happen without being destructive to other components that you added (within reason).

The current plugin supports most SOP nodes that output polygonal geometry. It doesn't currently support volumes or particles, though a future release will support heightfields (converting to Unity terrain). Also supported is the Curve SOP which can be brought in or created newly in Unity, then edited as in Houdini. Materials and textures are also imported. You can also send input data (geometry) and attributes (uv, N, Cd) back into Houdini. This ties in with painting attributes as well, which is supported.

For the upcoming update, we will have more documentation and tutorials, as well as a supported feature list. For best performance of how to structure your geometry, it really depends on the use case. Some objects are better packaged up whole and instanced (eg. rocks, static geo), while others should be in chunks for various reasons including better collision/physics performance, rendering, and flexibility for dynamic effects/changes. You'll have to play around to see what works, but the good news is that you're using Houdini so it shouldn't be hard to try various methods and test performance.

Currently, the documentation that can help you get started is here: http://www.sidefx.com/products/houdini-engine/unity-plug-in/ [www.sidefx.com]

Admittedly there is a lack of documentation in regards to usage such as the Unreal one. This will be addressed in the near future though.

As for the state of the Unity plugin, I can tell you that it will be getting a very well deserved update with lots of improvements in the very near future. It will have similar (more or less) features as the Unreal plugin. It is currently being actively developed though not in a state for public release yet.

If you have specific questions about the plugin, please post here.

This is probably beyond what the Unity plugin can do at the moment. This sounds like it requires runtime evaluation which the plugin does not support. On the other hand, you might have better luck on the general Houdini forums for a more general answer, so try asking there.

No it hasn't changed, so your edit should work fine.