Over the weekend I was trying to export a complex fluid animations to UE4 using VAT from SideFX Labs but kept running into glitched animation. I've narrowed this issue down by exporting one of SideFXLabs example files many times with different settings.

The project file: https://github.com/sideeffects/SideFXLabs/blob/Development/hip/vat_fluid_demoscene.hip [github.com]

I'm 100% sure my workflow is correct, I've checked a few tutorials, the most detailed I've found is this one

https://translate.google.com/translate?sl=ja&tl=en&u=https://houdinifx.jp/blog/labs-vertex-animation-textures-rop-%25E4%25BD%259C%25E6%2588%2590%25E3%2581%2597%25E3%2581%259Fvat%25E3%2583%2595%25E3%2582%25A1%25E3%2582%25A4%25E3%2583%25AB%25E3%2582%2592ue4%25E3%2581%25A7%25E8%25AA%25AD%25E3%2581%25BF%25E8%25BE%25BC%25E3%2582%2580%25E6%2596%25B9%25E6%25B3%2595/

My software versions:

Houdini: 18.5.351
SideFX Labs: 502
UnrealEditor 4.25.4
Unreal master materials: those provided in SideFX Labs UE4 4.25 plugin


My test results:

30 frames, 1K texture, no padding, exported 1024x783 px - works fine



240 frames, 1K texture, no padding, exported 1024x6453 px - works fine

240 frames, 4K texture, no padding, exported 4096x1673 px - works fine

So far so good, but to have UE4 texture streaming support, we need to pad it to the power of 2:

240 frames, 1K texture, padding enabled, exported 1024x8192 - broken, flat



240 frames, 4K texture, padding enabled, exported 4096x4096 - broken, filckering



I'm not sure if this is an issue with the texture export or the UE4 material? I'm setting "Pad X" and "Pad Y" material attributes correctly.

Once I have an example working end-to-end I would gadly share it with the community.