Vertex Animation Textures ROP 2.0 Released

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Hi folks. We've just released our first pass of an updated vertex animation textures (VAT) ROP.
You can watch the quick start video for Unity [vimeo.com] and for UE4 [vimeo.com]. Consider this a pre-release. If you have any feedback we'd love to hear it. Big shout out to Ben Laidlaw who did most of the hard work and was kind enough to share with us and the community.

I forgot to mention in the ue4 video that you should turn on “full precision uv's” in your mesh settings.

What can you find in the new version?
* Updated shaders and materials for Unity to work with the LWRP in 2019.
* Updated material functions for UE4.
* Tooltips (Detailed help card coming soon).
* Export presets for different game engines.
* If you double-click on the ROP after exporting you can see a debug version of the mesh and textures that were exported.
* Unity exporting will automatically update the material settings.
* Pad textures to power of 2 for texture streaming.
* 2 textures exported for extra precision when limited to 8bit textures.
* And a bunch of other stuff.
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cool!
can is there a limit to how many frames this can spit out (due to texture size)? or how dense a mesh?
could this replace alembic cache in terms of efficiency?
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Yup. Assuming you had a max texture size of 4096, you could have 4096 frames for a mesh that had 4096 vertices. Or you could increase your vertex count and decrease your frame range. So 6000 vertices would require two lines for each frame, giving 2048 frames.

It depends what kind of efficiency you're talking about and which engine you're running. One advantage of alembic files is the importer can filter the data to only use every other frame or some other kind of reduction in favour of performance. VAT just loads the entire texture onto the GPU. Some Alembic implementations also handle certain issues with shadows better.

And then there's also the type of export. Alembic is great for fixed point geometry (vertex count and order is the same for every frame). Fluid sims change every frame so VAT is the preferred solution.
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thanks for the reply!

I've been investigating different cache ways to bring in animation into unreal so I've had an eye on animation textures for a while.
With python being added to unreal maybe it would allow for some more ways to bring stuff into the engine more efficiently.

I'm guessing that the precision of the texture is based on the bounding box of the animation? in the link here [vimeo.com] the precision was a bit off, is that fixed with 32bit textures?
does the scene size have some affect on it? say if the bounding box is large or the animation is for example 1,000,000 units away from world space 0?

you say that alembic can handle some certain issues with shadows better? do you have an example on how that would be compared to using just animation textures?


I've found that even since unreal has streaming alembic cache since 4.22, it's still experimental. so large cache files take a long time to load in. I've experienced some taking 2 hours to bring in, and i have no idea if it's crashed or not while it's coming in. so another thought i had was to maybe batch load an alembic animation in parts. or if vertex animation cache is precise, textures seem like a faster way to load in clips to a mesh.

thanks!
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Hi Mike,

i tryed to follow your video step by step. But my mesh doesn't start moving in unity. You didn't push the play button, right? The animation starts in that moment, you applyed the texture. Is there any more dokumentation avalible?

(My texture is still purple, even though i changed the shader…)

I do miss something. Thanks for your help and your amazing work

Dominik

Attachments:
vertex.jpg (276.1 KB)

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Hello again,
I watched the “Vertex Animation Textures 2.0 UE4 Quickstart” over and over but I could not get it to work. VAT 1.0 looked like a ton of triangles when it wasn't working but this version doesn't show anything. When I have the wrong settings, I can see the triangle chaos, but as soon as I put in the settings from Houdini, it vanishes, and I don't even see it in wireframe mode.
I think it may be something with the textures. I've followed along but I noticed in the material when I have the texture set to HDR it wants the texture object to be “color linear” and when I switch it Vector Displacement it errors until it's switched “color”.I'm suspect that there's something up with the textures, maybe from import, but I really don't have any clues.

I'm currently trying the fluids shader.
Any help is very much appreciated.
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Couple of things to check. Have you checked the debug output in Houdini to make sure the mesh and textures are being created correctly? You can double click on the VAT node to see the debug view.
Are you using the material function code supplied with the VAT 2.0 node? The old code might not work with the latest version.
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Hi Mike,
I have followed your video “Vertex Animation Textures 2.0 Unity Quickstart” step by step to create a fluid effect form houdini to unity.Everything is OK until I found the material in mesh have a strange shadow,just like some triangle in the mesh always been flikering. I have no idea about if this is the shortage of this technich or I do something woring. The result in unity is like the picture below.

I used unity 2019.3.0 with URP Render Pipeline and Houdini17.5 with Game develop toolset 1.209 Release Stable Branch.
Any help is very much appreciated.
Edited by zhujing - Dec. 12, 2019 07:20:10

Attachments:
test_VAT_Animation.gif (354.7 KB)

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It looks like the resolution of the mesh is pretty low and that flickering is the constantly changing triangles. What does the mesh look like if you dive inside the VAT node in Houdini? Have you tried increasing the target prim count?
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Hello,again and Thans for your reply!
Yes,I have tried another five meshs just like below :


As the picture shows,even if the vertex has already been almost 30000, the faces also look like flitering.Is the vertexs of mesh still not enought?So How many vertexs should I use to acheive a better look in general?Because I need to use this in Android phone, I'm afraid of high count of vertexs will lead a poor performance.

Attachments:
test_VAT_Animation2.gif.gif (2.3 MB)

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But are you seeing that flickering in Houdini? If the fluid meshing combined with the polyreduce creates that jittering then you need to change the accuracy of the meshing.
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EDIT: Found the solution. Mesh was doublesided and had collisions, fixing this solved the issue.

Hey Mike,

so I'm trying to export a vertex animation of a simulation I did. This vertex animation will then be used in Unreal for a project I'm working on.
My issue here is that when I try to export a mesh I get an error as seen on the pictures.

Also I get 2 different interfaces when creating the VAT node from the shelf tool and when creating it from the tab selection.
(VAT from TAB selection is slower because it pre-cooks all the frames I guess?)

The error is about packed normals/ render position but I do not really understand what they mean by that.
I tried looking it up on google but unfortunately I didn't find any solution.
Do you happen to know why the export won't work?

I would like to share the Hip file but the cache I'm using is 6.7GB so it's too Heavy to post.

Also for the sake of clarity I'll explain what each pictures need to show:
1) Error message from VAT node created from shelf tool
2) Error message from VAT node created from TAB selection
3) UI of the VAT node created from shelf tool
4) UI of the VAT node created from TAB selection
5) UV's

Thanks in advance,
Edited by Nawfal - Dec. 18, 2019 08:45:25

Attachments:
Error_Message_VAT_from_Shelf_Tool.jpg (712.8 KB)
Error_Message_VAT_from_TAB_Selection.jpg (771.8 KB)
VAT_From_Shelf_Tool.jpg (716.7 KB)
VAT_From_TAB_Selection.jpg (747.2 KB)
UV.jpg (786.1 KB)

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HI. The shelf tool was still creating the older version of the VAT node. I've submitted a change to the github repo to generate the latest version of the VAT node.
As for your errors, it's really difficult to tell what could be causing the problem from the info you've provided. If you could share the hip file, even without the cache, I might be able to figure out the problem.
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Hey guys!

I'm just starting to fiddle more in detail with the VAT workflow on Unity.
I'd like to ask you Mike if it's possible to export custom attributes with the VAT node.

I found that there's an Import Attribute/Export Attribute tab that reads P, I tried typing a custom attribute but it just rendered the position regardless of that.

Is there anything extra that I should setup for this to work in my particular case?
What I want to do is follow Keijiro's example [github.com] and have some behaviors being driven by animated attributes from Houdini.

Any help or guidance will be very much appreciated Mike, thanks a lot! Awesome work ;D
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Hi Mike,

In my tests here with VAT (and I think you also had the same issue in the Unity video link that you added in your first post) I had a hard time with the rotation of each separate elements. It seems like there is something wrong with each elements pivot.

With scattered objects it seems less obvious, but with distinct objects (with angled velocity applied) it get quite crazy.

I will attach a simple scene file already ready for export to unity.

I will also attach a printscreen of the animation in houdini and unity, to try to show the issue. Both images should be looking the same, but there is something clearly wrong in unity.

I thought if it could be something related to gimbal lock, but I think it is probably something I did wrong.

Thanks for any insight you could possibly give me!

Cheers,

Rafael Bottari Martinez

Attachments:
VAT_test.hiplc (2.9 MB)
unity_issue.png (52.8 KB)
houdini_sim.png (268.6 KB)

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