Vertex Animation output from Houdini

Was wondering if you, or anyone, had any clues where I might need to check to get this working correctly. I’ve successfully gotten other fluid effects working in Unreal using the vertex animation export, but I’ve consistently gotten a jittery mess with this one:

Effect is supposed to be a solid with part of it melting away. Using shelve tools of “Melt Object” and “Heat Within Object” to achieve the effect and exporting using the method “Fluid (Changing Topology)”.

In Unreal I’ve checked Use Full Precision UV’s on the mesh, in the material put in correct values for Bounding max/min, checked appropriate normal_data/ pack_normal. In Houdini I’ve tried exporting many times with a variety of settings. Tried reading in different "Export Node"s, changing target polycount, texture size, equalizing edges… Still seem to get the same result.

Wondering if missed or forgot some important parts from the last time I created an effect from the vertex animation export.

I think your framerange is off. If you think it’s 128 frames, try setting it to 127.

That was actually my first thought, but I’ve messed with that as well. It’s entirely possible it’s something with how I built it in Houdini, as I’m still pretty new to it. Didn’t think I was doing anything too mind blowing, but I’ll probably try recreating the project and maybe exporting it at each step to see where and if it breaks. I’ll report back if I find something that’ll help save someone headache in the future.

Are you using the Beta version from github?

Houdini 16.0.633 and Unreal 4.16.1

Yeah, but are you using the vertexanimbaker that comes with that version of houdini, or the beta version on Github?

The one on github solves a lot of bugs like these.

Oh I see. Using the version that comes with Houdini. Where can I find the beta version?

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Thanks! I’ll give that a shot with the original project and see if I get something different.

Ok, so I feel like an idiot. For those who are as unfamiliar with Unreal as I am, when you have the mesh open and check “Use Full Precision Uvs”, simply hitting “Save” is not enough, you have to be sure to hit “Apply Changes” at the bottom of the section for it to take effect.

Thanks for the help @Partikel. Even though I was looking in the wrong places I plan on using this tool a lot so it’ll be helpful to have the latest and greatest version of it.

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Has anyone else imported the Rigid (Rigid Body Dynamics) version of this correctly in Unreal? I’ve done it successfully with the fluid setup but the rigid seems to have different material parameters and gotchas that aren’t mentioned in the posted videos.

For example, why are there 3 parameters for checking normalize data? Why are there 2 sets of bounding min/max values? If I apply the values supplied from Houdini to one set but not the other I seem to get closer (but still not correct) results in engine.

EDIT: FYI discovered the fbx being exported wasn’t applying the vertex colors to the mesh correctly. Some issue about the source mesh itself that I was importing into Houdini. The “gotchas” in Luiz’s videos are usually a good starting point for troubleshooting these issues. I might put together a short list for each of the export methods just for easy reference.

EDIT2: For some reason, in Maya, combining separate meshes in to a single mesh (freezing transforms and deleting history) doesn’t work for exporting the rigid method. Using a combined mesh as the source file that I’m fracturing in Houdini. The vertex animation texture export doesn’t assign the necessary vertex colors to it to read correctly in engine.

Hey Guys I’m having some issues getting a rigid body into UE4, I followed the videos from Luiz but the export in unreal is a bit off as you can see… any ideas?

https://drive.google.com/open?id=0B19GnpEaIGHXQ1VDVzUxbUhHNTg

Update1:

with some tweaking its improved but still getting some strange rotation going on

https://drive.google.com/open?id=0B19GnpEaIGHXNGhUNS1NS3BqdEE

Did you check this Parameter inside of your imported Mesh ?

I’m just asking, because I had some similar issue with fluid.

the high precision UVs?, yeah I did

It looks pretty similar to an issue I was having in the past. I asked Luiz about it and he had me get the latest version of the tool from GitHub: GitHub - sideeffects/GameDevelopmentToolset: A series of Houdini shelf tools that are geared towards game developers!

I think that had solved my problem (but introduced a new one I can’t remember) a while ago.

The problem, at least for me, that I had discovered was that combining meshes in Maya that were being used in the Houdini simulation, caused the tool to no longer write to the meshes vertex colors correctly on export. For the rigid body simulation the vertex colors represent the pivot point for a chunk of vertices. You’ll be able to see if that’s the issue by checking vertex colors on your exported mesh. If each chunk is a different color you that may not be the issue, but if the vertex colors are all the same (I think white) on the exported mesh, then that’s the problem. Either way getting the latest version of the plugin is worth looking at.

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Hey

Sorry for the late reply, getting the beta resolved the issue :slight_smile: but it seems to have issues with active and inactive regions, I will keep looking into this :slight_smile:
Thank you very much

https://drive.google.com/open?id=0B19GnpEaIGHXem85RTdrQ3VGWDg

Hello !
Anybody tried usign (soft) vertex animation and normal map one the mesh ? I tried but I have no idea of what I’m doing.

Hello! Someone else having the following issue with the “vertex_animations_textures”-node?

Using the RBD-method I get two bounding boxes instead of one called BBOX MAX1/MIN1. It outputs values when you render, apparently used for pivots but is never used within the UE4 shader. Using the values from the first set of BBOX-parameters makes the animation pretty much correct but sort of compact, with the chunks never reaching as far as it did in Houdini.

Here’s a screenshot of a super simple scene with a box just hitting the floor.
Capture

There’s and issue posted on Github for this specific problem here, but that was a while ago. Vertex animation textures broken · Issue #38 · sideeffects/GameDevelopmentToolset · GitHub

I’m using the latest update of the shelf and Houdini 16.5

Does anyone have a workaround for this issue? Should I just use the skeleton/joints workflow instead?
Cheers!

EDIT:

This being an issue posted on their GitHub got me confused; this is apparently not a bug at all.

With the correct settings for my specific case, i.e. unchecking “normalize” I managed to get it working.

I don’t know if this thread is dead, but I think I’m having a similar issue.

I’m using the Vertex Animation Tool to export a large destruction animation for use in UE4. Unfortunately, on the first frame of the animation, most of the chunks seem disconnected and are just a little bit off. They don’t line up properly, so it breaks the illusion that the large structure is slowly falling to pieces.

Is there a way to make this more accurate? I have turned on full precision UVs in my models, and it looks like vertex color is exporting correctly (I think- at least, every chunk seems to have it’s own color). I’ve also turned off normalizing from zero to one. I thought it might be a limitation caused by the size of my geometry, but I’ve seen this problem on much smaller sims, too. Is there anything else I can try?

Thanks, everybody!
Brian Kohrman

I found a solution to my problem. I needed to change my DOP import method to Fetch Geometry instead of Fetch Packed Geometry.

More details: