Houdini 16.5 Vertex Animation Texture Error

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22 posts
Joined: 3月 2013

I am trying to use the Vertex Animation Tool to export a Fluid sim to UE4 but I keep getting the following error when trying to export the textures.

Python error: Traceback (most recent call last):
File “”, line 3, in
File “CPROGRA~1/SIDEEF~1/HOUDIN~1.268/houdini/python2.7libs\hou.py”, line 17710, in getPixelByUV
return _hou.CopNode_getPixelByUV(*args, **kwargs)
OperationFailed: The attempted operation failed.
Failed to retrieve pixel information.

I have tried reducing the number of polys and checked that I have point normals, but I keep getting the same error. Anyone got any ideas what I am doing wrong?


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534 posts
Joined: 9月 2016
Hi Graham,

Sorry for the late reply, unfortunately I'm not an expert with the Vertex Animation tools,
but may I suggest that you post your question on the Houdini for Realtime forum [www.sidefx.com]?

You're more likely to get an answer on this there!
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394 posts
Joined: 5月 2017
Hey Graham,

Sounds like the texture isn't being generated which could be because of the path you've set for the export node. Make sure it's pointing to the object level node not the sop level node.

You can also right click on the VAT hda and choose “allow editing of contents”. Then dive inside and find fluid_copnet/calculate_delta node and make sure it's producing an image. You can check in the composite view.

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1 posts
Joined: 11月 2017
Hi Graham,

I think I've found the problem. I also had the same error when trying to export from Vellum to Unreal with gamedev VAT.
After a lot of searching, I've found that the problem was actually the scale of my mesh. For me it was too big and I had to reduce it from ‘'1’' to ‘'0.1’'. the scale in houdini is in Meter, but I imported my mesh from Maya (which is in Centimeters).

Hope it can help you!

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