Vertex Animation Textures ROP 2.1 Released

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Hi folks! Version 2.1 of the Vertex Animation Texture ROP is now available.
You can watch the quick start video for Unity [vimeo.com] and Unreal [vimeo.com].

So what's new?
  • A Unity package with URP compatible shadergraphs is now included.
  • An Unreal content plugin with materials, material functions and helper utilities has been added.
  • Power of 2 textures are set in the material with a ratio now instead of two separates values.
  • Shader logic has been changed for rigid exports that ensure better precision during playback. This does have an undesirable impact on the start frame because of precision issues with vertex colours being used for the centroids.
  • Some UI cleanup to help discoverability of commonly used parameters.
  • Updated docs.
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Hi Mike.

I have problem with content plugin.

After following the quick start video step by step, in UE4, I do can see all folders of SideFX_Lab's, but no item in there.
The uasset files are in the correct directory but don't show up in the content browser.

May the version of UE4 are sensitive?
My version of UE4 is 4.24.

Thanks and regards
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Akira_Vercoutter
My version of UE4 is 4.24.
I authored the content plugin with 4.25. Let me check on my side and get back to you.
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I've added a content plugin for 4.24 which will be available in tomorrow's daily build of SideFX Labs. Unfortunately the utility functionality isn't available but the materials and material functions should be there.
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Hi Mike.

mikelyndon-sesi
I've added a content plugin for 4.24 which will be available in tomorrow's daily build of SideFX Labs. Unfortunately the utility functionality isn't available but the materials and material functions should be there.

Thank you for re-authoring.
It works fine now: I actually updated UE4 to 4.25.
The content plugin utility is pretty handy!

However, may be I have an issue with the “Pad to pow of2” function.
The “pow of2” version of VAT appears very flickering in UE4.

Is it normal or an issue?
When the compression setting of the pos/rot texture are set to “HDR(RGB, no sRGB)”, the symptom disappears.

I attache a movie of my case(the “pow of2”version on the left, the non-“pow of2”version on the right).

Cheers

Attachments:
VAT21_RBD_pow2_issue.mp4 (2.2 MB)

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Akira_Vercoutter
The “pow of2” version of VAT appears very flickering in UE4.
Have you set the padded ratio values? Does the flickering show up in the debug view in Houdini?
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Hi Mike!

mikelyndon-sesi
Have you set the padded ratio values? Does the flickering show up in the debug view in Houdini?

Yes the ratio values are correctly setted.
But for the debug view in Houdini, I cannot check them because it crushes when dived in.
To add, I also receive a warning message when opening the scene.

I attach the scene file, the capture of texture detail tab in UE4, and the log.


Cheers

Attachments:
learning_RBD_VAT21_02.hiplc (4.5 MB)
pow2.jpg (162.2 KB)
Load_Log.txt (577 bytes)

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I have copied over the Plugin folder for unreal 4.24, and I see the SideFx Labs content in the content browser, but I dont have access to the option for importing the data table or the script for changing the texture image settings. Is there an additional installation step for the plugin?
Im on labs build 497
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DrMuerte22
I dont have access to the option for importing the data table
Unfortunately, because the utility scripts are only available in 4.25, the data table struct is only applicable to 4.25 too.
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Akira, it looks like that's a limitation of the compression setting. There doesn't seem to be anything wrong with the math when using pad to power of 2. I think you need to use HDR Compression.

The warning messages are from the way the geometry has been fractured. You probably have some very thin slices.
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Hi, I have issue with VAT when skin mesh cache is on in UE4 (due to raytracing requirements), when it's off - works super well, with caching on - animation gets wobbly. Is there anything i could do to avoid that? Thanks,
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Hi mike.

Thanks for your reply and revisioning in the math.

mikelyndon-sesi
Akira, it looks like that's a limitation of the compression setting. There doesn't seem to be anything wrong with the math when using pad to power of 2. I think you need to use HDR Compression.

It is good to know, I will use HDR Compression.

mikelyndon-sesi
The warning messages are from the way the geometry has been fractured. You probably have some very thin slices.

Yes I do think having very thin slices.
Is it the same cause for the crushing issues: does very thin slices provoke crushes in the debug mode in Houdini?

Cheers
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Hi, I think I must be missing something - I can't find the Labs documentation, in particular the VAT 2.1 release. I looked on a github and google and the the Houdini docs. Could someone point me in the right direction?
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This is a really great feature, is there a way to stop the animation from looping?
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Hi Mike! I was comparing the new VAT material function with an old one from last year and was haunted by a couple of changes I couldn't understand… Do you mind explain them a little bit?

The first one is the subtract node appearing after the quaternion rotation:


It subtracts the rotated vector by the pivot value. This operation isn't in the old version. Does this mean that the info stored in the the position texture has completely changed meaning? Could you explain the decision?

The second one is this part right about the unpack pivot block:


They used to be something like this:


To me it feels like they should always give the same result… Is there anything I missed?

Thanks!
Edited by drewhong - Aug. 20, 2020 13:28:10

Attachments:
image (10).png (164.2 KB)
image (8).png (168.1 KB)
image (9).png (70.8 KB)

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Hey drewhong,

Basically the previous method was using a hack to get around how DOPs sets the pivot from the first to second frame of a sim. This worked most of the time at the beginning of the animation but the VAT result later in the animation would start to drift from the original. You could see this quite clearly with rotations.

In order to fix that I also had to change the order of operations to handle moving the object to the origin, applying the rotation, and then moving back to the current time's position.

So the new method is more accurate overall, but you might notice a slight break of an object after the first frame because of precision issues with the orient attribute in the texture.

Hope that helps.

Mike
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Hi Mike.

What is for the “Pack Pscale into Position Alpha” feature?

I would like to scale the chunk of the fracture with rigid body.
Somehow, I want my chunks scale down and disappear before they hit the ground.
Is it possible?

Here is my workflow.
In Houdini, I create a pscale animation(in point attributes) after the simulation.
However the exported position map result with 100% white value in alpha channel.
Is there a proper way to export the pscale attribute?
Or did I misunderstood the “pscale” feature?

Also in UE4, it seems that the VAT material are doing nothing with the alpha channel of the position map.

Cheers.
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I'm having a spot of trouble with the export for the VAT.
The rotation comes through in UE4 just fine but the position isn't being generated. I'm sure I'm doing something wrong but I can't quite figure what.

I'm using rigid to reduce cost, but it isn't an RBD simulation, though I have tried running it through that pipeline without changing the output itself. No joy there either.

As a side note, when I attempt to supply a pivot it appears to break the exporter so I'm guessing I'm supplying it incorrectly.

Any help would be greatly appreciated!

UE4 4.24 (custom build)
Houdini 8.0.532
Labs 561

Attachments:
mops_tank_treads_embedded.hip (3.2 MB)
vertex_animation_textures1_mesh.fbx (29.6 KB)
vertex_animation_textures1_pos.exr (1.4 KB)
vertex_animation_textures1_rot.exr (3.3 KB)

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mikelyndon
Hey drewhong,

Basically the previous method was using a hack to get around how DOPs sets the pivot from the first to second frame of a sim. This worked most of the time at the beginning of the animation but the VAT result later in the animation would start to drift from the original. You could see this quite clearly with rotations.

In order to fix that I also had to change the order of operations to handle moving the object to the origin, applying the rotation, and then moving back to the current time's position.

So the new method is more accurate overall, but you might notice a slight break of an object after the first frame because of precision issues with the orient attribute in the texture.

Hope that helps.

Mike


Hi Mike,

Thanks for the reply! It really helped. So to my understanding, the position texture used to store the offset of each piece against the first frame (or piece pivot); now it's storing the offset against the object pivot.

(Looks like you have left SideFx. I really appreciate that you showed up and answered this random question… Wish you good luck in whatever you are doing next!)
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Where is VAT 2.1 ? I am using Houdini 17.5.173 and 18.0.348.

I cannot find it in any branch of the repository in the GitHub. The version of VAT I've found in Development branch is 2.0. I've checked it in Houdini, but also you can see: https://github.com/sideeffects/GameDevelopmentToolset/blob/Development/otls/rop_vertex_animation_textures.hda/Sections.list#L4 [github.com]

I'm interested in this version because VAT 2.0 doesn't support Unity URP.
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