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Skyrig VDB to Polygons Mesh Cannot Be Saved March 8, 2020, 11:25 a.m.

When creating a skyrig (H18 v391) and converting it to polygons, the output ROP does NOT save the information. It saves an empty file.

Here's the output (obj for readability - bgeo is same) for polygon mesh generated from the skyrig and converted using either direct Convert VDB node OR Convert node (on a volume as described in the video attached) and saved via Rop Output node.

# File exported by Houdini 18.0.348 (
# 0 points
# 0 vertices
# 0 primitives
# Bounds: to

Plugging in a simple grid into the Rop export node yields data (points and polys) as expected.

In the video below (which is what I'm following) it talks about a quirk in Houdini where meshes from the Skyrig yield EMPTY fbx files, so he saves it to a bgeo file and reimports it to bypass that issues.

Now, with H 18 it seems even saving to bgeo yields an empty file. I just have to right click save the file, which breaks the proceduralism. []

What to do? How can we export converted skyrig geometry out of houdini?

Thank you

Error Outputting Splatmaps Sept. 6, 2019, 4:31 p.m.

If you are getting this issue with the PDG workflow (using PDGAssetLink), then I suggest trying with the regular (non-PDG) path to rule out bugs with just the PDG workflow. The regular terrain generation differs from the PDG generation so it is possible for bugs (or missing features) to exist in one case, but not the other.

If you are specifying an existing TerrainLayer, I suggest trying another TerrainLayer with different size or properties. My gut feeling is that the SetAlphamaps error is a clue that not all is right in the internal terrain state. Note that since you are specifying an existing TerrainLayer, the plugin will just assign it to the TerrainData, and won't check if its compatible. Additionally, it might set some properties on the TerrainLayer if you have specified them via attributes.

Are you able to generate a TerrainLayer (via a new heightfield layer in H), and use that instead? If that works, then check that the sizes match between the existing and generated TerrainLayers.

If you can attach an HDA, I can take a look as well.

Hello Seelan,

Thanks for the help.

So as per your advice we broke apart everything and tested it individually, NOT through PDG.

Turns out the U console error is from the very first HDA from a heightfield erode node and the layers it puts out (bedrock, debris, water etc)

So if we delete those with a blast, the error goes away BUT then we cannot process the chain later on. So the error disappears but then the texturing HDA doesn't seem to work properly with the input that's coming in that's missing those layers. (see attached initial hda - though I doubt it will be useful)

It's hard to debug this because in Houdini everything works perfectly. Even in the piped debug session.

Other things we tried: updating to HE 364.

One question that we are asking ourselves is if there is a problem with HDA's that contain both ‘regular’ geometry and heightfields?

Is there a way to get what node is problematic and a more specific error message? Read the debugging page ( but again, since our problem does not show up in Houdini itself, but rather in Unity, it doesn't give us any insight.


Error Outputting Splatmaps Sept. 3, 2019, 4:13 p.m.

The error sounds like a sizing issue with one or more of the terrain layers. Could you isolate the layers and try them out one by one, if you are using different sizes?

Note that there has been quite a bit of changes to the Unity terrain generation as logged here: []
Especially 17.5.302 onwards.

If you are able to, I suggest you move up to the latest 17.5 builds to keep up improvements and fixes. It might require some changes to your HDA. But the improvements have been based on feedback that is better aligned with desired production workflows.

At the least, you can try out the latest changes in a separate empty project to see if it makes sense for you.

Hello Seelan,

Thank you for the help.

We did as you suggested: Upgraded (360) and then tried to see where the problem stems from. Just to make things clear, there are absolutely no issues in H. However, in order to eliminate possible issues we removed all relative links. So the sizing is now hardcoded in at 4097 (with 1 being the resolution).

The issues is that we don't really know what problem we're looking for or how it is logged.

When you say “The error sounds like a sizing issue” do you base this on the Unity console message that says “Texture rectangle is out of bounds”?

That message pops up from our first HDA in the chain even after we've set the terrain size so there are no discrepancies (note: there weren't any discrepancies before either). I should note that the heightfield comes through just fine in U.

Could you please explain what steps to debug this. In H everything is fine and the U console doesn't give too much info. For example: not sure what those warnings are all about, what is Part with id 1 etc?

Thank you.