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Unity Help & Support Thread Sticky

A topic by SideFX created Aug 07, 2020 Views: 1,954 Replies: 34
Viewing posts 1 to 16
Host(+1)

Unity has graciously offered to provide game developer support during Houdini Game Jam! Use this thread to ask questions related to Unity if you need help. Also, check out Houdini Engine for Unity on the Unity Asset Store here.

Do the HDA assets from the Toolkit and in Houdini Engine work with URP in  Unity?

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The tools and the Houdini Engine should work with all render pipelines. The project included in the files is build with the default 3D template of Unity. So the plugin you can get here https://assetstore.unity.com/packages/tools/utilities/houdini-engine-for-unity-163415 or in the Houdini files on your computer. The tools (HDA's) you might need to drag and drop them in your current project.

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I am trying to Render a VAT 2.0 output node. But the .exr files are being saved as 1x1 in size, even if I've selected 1024 in the dropdown. I don't think I see any error messages. What could be wrong?

I found the problem: my "SOP Path" field was empty. Setting it to the geo's out node fixed my issue.

Submitted (1 edit)

I have had an issue with Terrains following this video series here I can get the Live Link to run the HDA steps however when I go to look at the terrain  it appears to be unable to load the mesh data. Please see https://filebin.net/pqz95tjbn1huwq9d for the HDA and HIP files.

The simplest hack way to set up the terrains for Unity is to use/duplicate the example TerrainGenerator.hda from the Houdini Engine integration "Assets\Plugins\HoudiniEngineUnity\HDAs". For a very quick explanation of the setup and how to make larger worlds is to follow the steps here https://www.sidefx.com/docs/unity/_terrain.html . This following citation does not use PDG, but it will get you going quickly. 

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Howdy!

I’m Mike Geig, a demo content creator at Unity. We absolutely love being involved in game jams (it's that whole "we believe the world is a better place with more creators in it" thing). So many amazing things can come out of a game jam, from a new game idea, to skills development, to meeting new people and building new friendships. So we’re really happy to be part of this one, with SideFX, and we’re looking forward to seeing what people can come up with in the next week!

We’ve got a few people ready to keep an eye out for questions on working with Unity, in case you run into problems. We’ll be triaging as best we can, and trying to be quick with responses so you don’t get too stuck (though times might be slower over the weekend).

Also, if you haven't seen it yet, check out Bolt visual scriptingwhich is now included in all Unity plans!

Hello, yes, newbie with a question here. As far as I can tell Houdini is used to streamline the process of creating 3D assets and create cut scenes, but I wonder if it is possible to modify procedural properties of those assets in runtime? For example if, instead of laying out game level beforehand in editor, I want to generate map topology randomly when loading a scene and let say I want to place some random houses with random amount of floors... randomly and you know, that sort of stuff. Or maybe I want to use it to create some sort of special effect in real time. Thanks

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Houdini is editor only and doesn't support runtime

I am putting together a blocky robot in Houdini. How can I use the URP shader to "preview" in Houdini?

I don't think Unity's shaders are compatible in Houdini since they're unique and distinct renderers 

Follow up answer: So you can't use the URP shader but you can use the /mat/principleshader and set all the relative textures on the object. Then on your object assign the shader. If you have multiple materials on a single object you can do the same at SOP level with the material node and multiple /mat/principleshader.

Submitted

How to people organize their HDAs - do you keep them with unity and then manually copy them to your Unity project asset folders?

Submitted

I create a Houdini project with all it's folders right inside my Assets folder in my Unity project.

Projectception works fine, and then I just use any .HDA directly from my hda folder and if I need to test something I just put it on the geo or text folders.

So I have both Unity and Houdini open and save the tool in Houdini and see the changes immediately in Unity.


I have never had any problem with that workflow, and I can even have my Houdini files synced with my repository.

You can also set the $HOUDINI_PATH environment variables prior to launching Unity and Houdini in a shell such as a batch script. This is what is normally done in a production environment. However, in the case of the houdinijam the method provide is the simplest and straight forward approach.

Submitted

Hey I have a question!

When creating geometry in Unity, Houdini Digital Assets can separate geo by group names so unity recognizes each one as a separate object.
Under asset options you can check "Separate by groups".  This unfortunately sets each object's transform as 0.0.0. 

Assuming we know the position and rotations of each object in houdini, How can we tell Unity what the world transforms of each group/object?

Also do the curve points inside of unity now work with the snapping tools. I used to have to hack the script to allow me this. If not how could I implement it now?

Are you using the Houdini Spline tool?

I made an hda that uses the curve input as an editable node in unity.. I create a curve in unity with the editor. I am assuming this is the same thing. 

Yes that's right. I asked because Houdini Engine provides the option to do HoudiniEngine > New Node > Curve which makes a separate HDA that is a wrapper around the curve sop in Houdini. You then can supply this HDA into your chosen tool. You could also add the curve sop in your HDA or use a third party spline package.

So to enable snapping, you can pre-adjust snapping options with Edit > Grid and Snap Settings... Make sure you change the Handle orientation to Global. Then when you create your spline HoudiniEngine > New Node > Curve you can hold Ctrl while clicking your points. I upped the snap distance from .25 to 1 to make the results more visible.

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Cool! thanks

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Hi everyone I'm Bronson! Like Mike I'm also a content developer at Unity and I'm here to help as best I can!

Submitted (1 edit)

Hi Bronson,

Thanks for joining us!
I was looking through the Engine / Unity docs and it lists the use of groups as a means of creating multiple game objects from geometry produced by n HDA. We got this to work but in doing so the game objects all have an origin of 0,0,0 but their pivot seems to be in the correct location. Is there a flag / attribute we can use to tell unity that the pivot we see in unity is the location in worldspace location of the gameobject?


As I understand it not if you use groups as a means of splitting up geometry. You need to set up your geometry as objects in Houdini for Unity to get the information of transformation.

Submitted (1 edit)

In our case that would be hundreds of geometry nodes, I imagine we need a different approach. I was looking into using instances instead but I'm not sure if each instance gets it's own independent transforms or if they show up as a group with a single central transform to all instances. 

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As far as the object level geometry node. You can set up a houdini python script to do this. The SideFX Labs static fracture export will do this for the static frames. You will need to add this to bottom of your SOP network, and adjust the script so it writes it within an editable object level HDA.



You can do instances too. Instances will be more performant than as geometry nodes are straight GameObject conversions. You can use the Copy To Points sop node set to pack, or use the instancer at object level. The former setup is quick and straightforward. The later is more complex but more scalable. EDIT: this method does give each instance it's own transform like you were asking



A third option is to use the Tree or Prefab instancer https://www.sidefx.com/docs/unity/_terrain.html#Terrain_Scatterring. I do not believe this will carry the parent transform though as originally requested.

Submitted

That's so cool! Thanks so much, I'll give this a try shortly. 

Are there URP equivalent shaders available for the shaders in the Houdini Engine package?

Unfortunately not. As a developer myself I would also love to have this.

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Follow up: I threw together some Shadergraph versions of the Houdini Engine shaders over lunch. I didn't have a chance to properly test them, but at a glance they look equivalent, and since they're made in Shadergraph they'll work in URP.

https://drive.google.com/file/d/1Zbb1GzHym5nrncu6r3SsHpxCfkWurGkx/view?usp=shari...

Oh wow, thank you so much! I don't think I'll be able to add anything to this jam but I'm definitely thinking of adding Houdini in my main Unity project workflow as I get more and more familiar, super exciting stuff!

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That's great to hear! I've been a longtime Blender user but I've also been incorporating Houdini into my workflow as well and I think it adds a ton of value!

Submitted

Help! We were submitting last minute and our upload didn't save, we probably uploaded a couple of seconds after the deadline. Is there any way to submit still? We worked really hard :(

Submitted

Similar issue for us, the uploader failed mid upload and when we went back the button was gone. What should we do?