022bd37c8b74470d
Hello! I made an error when exporting Unreal using VAT fluids. lookup export failed. Hope that helps.

how????

Hello! I was wondering if anyone has had any luck getting a fluid VAT to work with VFX graph. In UE, it was pretty easy to get particle information piped into the shader. My current problem is: I got VFX graph to move my particles around, spawn multiple particles, but my VAT never reconstructs (stays as a cloud of tris).

So far I haven't had any luck on getting a VAT to work with vfx graph in Unity. Any help would be appreciated! Thank you!

I got a problem that RBD normals looks messed up on forward renderer in Unreal4. For it to work properly U need to find inside a fragment that is making the normals. Find tangent calculation and just pass it outside the function - then connect it into tangent on material. That should work.

Hi Everyone,

I've updated my pipeline from VAT 2.1 to VAT3.0 few weeks ago as Unity 2021.3.X (LTS) has resolve the shadergraph compatibilities and wow, it's impressive how things work well. The frame interpolation is really a plus on this one.

I dive into the shaders to understand how it works and I have a few questions/feedback about it.
Here is my setup for the tests:

1. Unity 2021.3.X (LTS) URP (the model) / HDRP (the test)
   
2. SideFXLab 19.0.657 / SideFXLab Dev Branch from Github
   

HDRP Target issue
This is not an issue, but the shaders are targeting URP so they will not directly work in HDRP.
The shaders target Univeral Render which is unknown in HDRP. Simply putting HDRP works as a replacement work.


Surface Normal
The Fragment normal Space is in Object Space Normal so the shader compute everything for this mode (the shader converts Tangent space normal map in Tangent space).

When converting the shader for HDRP the Fragment Normal Space is automatically set in Tangent Space by default. In this configuration the surface normal will never be applied to the surface as they are output to the wrong space.
Here is a test with a simple brick wall normal map on the soft body unity demo file.


To work in HDRP you will have to set the Fragment Normal Space in Object Space to see the normal map applied.


But as Unity tends to target Tangent Space as the standard for HDRP, I was wondering why to target Object space.
Is there a specific reason to choose Object Space on the Fragment ?
Especially because the normals can directly be grabbed in Tangent space directly. To do so will avoid use to convert the normal map from Tangent to Object Space and the result seems correct.



Shadow map on the Particle SPrite Billboard
I saw a strange behavior on the Particle Sprite shader (URP and HDRP), the shadow map seems to be offset and we always get shadow on part of the billboards which should be lighted. It seems dependant to the view director as these shadows move with the camera view.

trying to export VAT for an animated geo.
The animation in Unity seems exaggerated. its not correct
Can someone export the vertex textures to check in Unity? i cant pinpoint the source of the problem, but i think it is related to the original geometry and not the unity settings

papsphilip
trying to export VAT for an animated geo.
The animation in Unity seems exaggerated. its not correct
Can someone export the vertex textures to check in Unity? i cant pinpoint the source of the problem, but i think it is related to the original geometry and not the unity settings

Haven't found a solution to this yet. the point count stays the same otherwise the exporter wouldn't work. Could there be some weird geometry property that messes up the export?

Any tips?

@papsphilip, I've made a few tests with your file without any great success, but to me it looks like a problem with the pivot point.
I made a test where a reset the pivot of your animation at the origin to check how it behave and it appears to have an offset after the VAT export.


Maybe the file has an error directly in the alembic?
Do you have the source file from the Alembic?

alexr25
@papsphilip, I've made a few tests with your file without any great success, but to me it looks like a problem with the pivot point.
I made a test where a reset the pivot of your animation at the origin to check how it behave and it appears to have an offset after the VAT export.


Maybe the file has an error directly in the alembic?
Do you have the source file from the Alembic?

thank you for taking the time! i am still investigating this myself with no success.
Here is the filecache attached i moved the geo to the center, i don't know if that helps.

Did another simple test with a sphere moving around the center and its not working either.
i am beginning to think this could be a VAT rop corrupted HDA?

@papsphilip I've tested your sphere scene, it's working properly on my side.
I am using the sideFXLab package 19.0.657
I haven't test your filecache, I will try later.

alexr25
@papsphilip I've tested your sphere scene, it's working properly on my side.
I am using the sideFXLab package 19.0.657
I haven't test your filecache, I will try later.

Could you please upload the VAT export folder (geo,tex,unity) so that i can try in Unity on my end?
Maybe my VAT rop is messed up

when i copy the VAT rop i get this message:

File "C:/PROGRA~1/SIDEEF~1/HOUDIN~1.383/houdini/python3.7libs\nodegraph.py", line 166, in handleEventCoroutine
pending_actions)
File "C:/PROGRA~1/SIDEEF~1/HOUDIN~1.383/houdini/python3.7libs\nodegraph.py", line 728, in handleEvent
self.applyAdjustments(uievent)
File "C:/PROGRA~1/SIDEEF~1/HOUDIN~1.383/houdini/python3.7libs\nodegraph.py", line 937, in applyAdjustments
connect_outputs_to_multi_inputs = False)
File "C:/PROGRA~1/SIDEEF~1/HOUDIN~1.383/houdini/python3.7libs\hou.py", line 14873, in copyItems
return _hou.Node_copyItems(self, items, channel_reference_originals, relative_references, connect_outputs_to_multi_inputs)
hou.OperationFailed: The attempted operation failed.
Warning: Problem while synchronizing child node:
Warning: Skipping unrecognized parameter "embedmedia".


and when i create a new one i get this:

Warning: Skipping unrecognized parameter "embedmedia".

hello guys, Im currently trying the RBD VAT workflow on UE5 and when I try to import it in UE, the fbx is skipped :
"Unable to triangulate "MESH" : it will be ommited"

does it ring a bell to anyone ?

papsphilip
Could you please upload the VAT export folder (geo,tex,unity) so that i can try in Unity on my end?
Maybe my VAT rop is messed up

I've made a new test with your filecache and the problem seems to come from your geometry.
Using softbody VAT with your filecache didn't work. I try to change the topology to check if it comes from it.
I applied a polyreduce and export it as a Dynamic Remeshing VAT (as the number of prim change over the frame due to the animation).
The result is correct inside Unity.

I will recommend to check how your mesh is constructed, the problem might come from it.
Here is the exported VAT.

Hi, MaiAo! I am using Houdini VAT3.0 for Unity2021.3.4f1. I have a question. If I want to implement the Shadergraph in URP_VAT3.0 using Unity Shader (C for graphic), how do I do it? I hope to get your help. Thanks again!

alexr25

papsphilip
Could you please upload the VAT export folder (geo,tex,unity) so that i can try in Unity on my end?
Maybe my VAT rop is messed up

I've made a new test with your filecache and the problem seems to come from your geometry.
Using softbody VAT with your filecache didn't work. I try to change the topology to check if it comes from it.
I applied a polyreduce and export it as a Dynamic Remeshing VAT (as the number of prim change over the frame due to the animation).
The result is correct inside Unity.

I will recommend to check how your mesh is constructed, the problem might come from it.
Here is the exported VAT.

Thank you!! unfortunately the files you produced are not working for me inside Unity. i get this weird distortion whatever i do.
i have SidefxLabs cloned from Github - current Development branch - updated regularly.
installed URP_VAT3 package into Unity.
created URP Render Pipeline in Unity
I am running Unity 2021.2.19f1

but i am still getting what you see in the video.

i cannot even get the sphere animated correctly.
Since i tried your MEDUSA VAT export files and it didn't work, i am guessing the problem lies somewhere in Unity(?) but i have no idea what. The package is installed and all presets are there. Also the URP installation was straight forward from Unity's site

https://docs.unity3d.com/Packages/com.unity.render-pipelines.universal@7.1/manual/InstallURPIntoAProject.html

creating a URP Asset(with Universal Rendering)

Is there way to play Vertex Animation Textures in Houdini? Have some problems playing in Unreal and want to make sure it's Unreal Engine issue and textures themselves are correct.

I've found a bug in Unreal Engine 4.27 SideFx Lab plugin for VAT HDR/Non HDR Textures scripts - it doesn't actually apply texture settings.

Here's the example where I applied all the setting with the scripts but result was bugged. Then I've just changed texture settings and changed them back (it's kind of updated the texture) and now it's fine.




Example of applying all texture settings manually (it works):



I guess we need to somehow add force texture update in the scripts to make them reliable.




UPDATE:
I've managed to solve it in blueprint, here's the description - https://forums.unrealengine.com/t/set-compression-texture-settings-from-blueprint-not-working/426562/5 [forums.unrealengine.com]

Hi MaiAo! I am trying to write a custom VAT RBD shader, I have done the vertex position transformation, but I don't know how to do the rotation, because it is hard to read the Pivot transformation part, can you express in code how to do this step.

alexr25

papsphilip
Could you please upload the VAT export folder (geo,tex,unity) so that i can try in Unity on my end?
Maybe my VAT rop is messed up

I've made a new test with your filecache and the problem seems to come from your geometry.
Using softbody VAT with your filecache didn't work. I try to change the topology to check if it comes from it.
I applied a polyreduce and export it as a Dynamic Remeshing VAT (as the number of prim change over the frame due to the animation).
The result is correct inside Unity.

I will recommend to check how your mesh is constructed, the problem might come from it.
Here is the exported VAT.

i finally fixed it.
i didn't change my mesh but i made sure the pivot was always at the origin, which i believe was suggested at some point by you as well and it turns out it makes a difference.
Moving the pivot for some reason, i don't know if this is a bug or if i should RFE it but after importing it to Unity you can see the whole animation being exaggerated like the values are stretched or something.
Another thing i did which i am not sure if it made a difference because by now i have tried lots of stuff, i opened my project in Unity 2022.1.15f1 instead of 2021.2.7f1.


The whole pivot problem feels like a bug to me, should i submit it?

papsphilip
i finally fixed it.
i didn't change my mesh but i made sure the pivot was always at the origin, which i believe was suggested at some point by you as well and it turns out it makes a difference.
Moving the pivot for some reason, i don't know if this is a bug or if i should RFE it but after importing it to Unity you can see the whole animation being exaggerated like the values are stretched or something.
Another thing i did which i am not sure if it made a difference because by now i have tried lots of stuff, i opened my project in Unity 2022.1.15f1 instead of 2021.2.7f1.


The whole pivot problem feels like a bug to me, should i submit it

Nice to see you found the issue
I am not sure about the Unity version as I didn't have any problem with various versions. But, about the pivot, I won't consider it a bug, but more a design specification. It's my understanding that VAT compute the position of the vertex inside a bounding box which will rely on the pivot point of your object. Having the object outside the pivot will enlarge the box so you might loose precision in the position texture.
Also, I think it would be better to keep the pivot at the center of your shape (or at a convenient position for orientation) in order for you to move the Game Object on the scene. You can then rotate or move the element without any translation problem due to a pivot outside the game object. For example You can use your animation with a VFX graph and simulate a bunch a Medusa where their position are directly managed by the VFX graph.

Hope this help