[HOU-1836] Vray Texture Bake issue - baking UDIMs

[chakarov]

Hello again david.anastacio , fix cases where V-Ray is not installed or set in houdini.env is added in last nightly build. There is a toggle in "Debug" tab called "Force V-Ray env variables" it is enabled by default. Can you try if it works for you.

[david.anastacio]

Hi,

Thanks chakarov, after a long day testing it I have good and bad news.

First test after updating to VRay build:7051 from 01 May, the same test scene was finally rendering as expected, UDIM tiles were getting rendered. But after some more tests and versioning up the file some times, it stopped working, was back at "exit code1" in TOPs. Going back to the original file got the UDIMs exporting again, but for example copying the same bake node to the file that wasn't previously working, made that copied node stop working. After some time I just gave up and started a new file from scratch, TOPs haven't thrown any error since then.
Not sure what was wrong with those other file versions, all vray baker nodes we always created from scratch. I'll report if we have more problems with this.

Then I proceeded to test the UDIM export in bigger meshes, production models with 150-250 UDIM tiles, 10-30M polys in alembic format. The 2 models I tested with I only got black frames exported, either in single UV or UDIM mode. The alpha was also completely black which might indicate either the geo or the UVs are not read by the render. When rendering the models normally with shaders applied there is no issue, just when trying to bake the textures.

I tried building a test scene for you to see this, but was quite hard, the same exact behaviour was not achievable through simple objects. This Monday I'll try to evaluate if it's possible to send you one of this models to test.....
But in the meanwhile in the test scene I put together you can see that the tool works in geometry that is inside Houdini, but that same geo exported into alembic and imported back the UDIM tiles stop getting exported.

Here's the link to the test scene (was too big to attach): https://we.tl/t-aIQ7wAvBec

There are quite a few examples in it. In the last example on the right, it also renders all black like in the production model, but I'm not sure is the same issue.

Not sure if this could be related with the UV issue I reported in this post: https://forums.chaosgroup.com/forum/...-in-image-file

And one last thing, a feature request for UDIM render, the UV range works, but would be way easier to just use the UDIM number, and even better if we could use ranges (example:1001-1050, 1070-1100), since a lot of models have "holes" in their UDIMs and we could skip this by using a range instead.

Best,
David.

[david.anastacio]

Hi again,

Small update, I gave it another go today and tried to isolate the problem. Trying to go really basic and not even using the vray bake tool, just a direct vray render node set to bake. There is definitely something wrong when using the alembic as the source of the bake tree, the same geos exported as bgeo (unpacked and converted to poly before export) makes the geo bake correctly again.
The strange part is that the production model I mentioned before that wasn't working, still doesn't work even when baked to bgeo....although they have the necessary attributes as you can see in the image attached.

I'll try do see if I can get more info/meshes tomorrow.

Best,
David.

[chakarov]

I have a little progress here, manage to render something through TOPs and geometry as alembic, but still need to find out what is causing the problem.

[david.anastacio]

Thanks chakarov, I really appreciate all the effort you guys are putting into this.

Since the production models had some different issues, I'm preparing one to send now. Not the same asset I used before (that one I could't send), but I found one I could send that also has issues.
I'm still waiting on the ftp info, but then I can send it to your e-mail?

Best,
David.

[chakarov]

What I find so far is that the problem is the same as before. When V-Ray is not installed or set in houdini.env file, process started through TOPs does not inherit all V-Ray env variables even if they are explicitly set within TOPs.

[david.anastacio]

Hi again,

I just sent to your mail the FTP access, and I uploaded an asset where having issues with.
TOPs have been running and saving files today, not sure if that is still an issue still. I think the new environment variables are doing the trick.
In the asset I sent you you can see that even when NOT using the UDIM bake (TOPs) it only renders black elements, even if i try using a Vray render node set to bake, still just renders black in the elements.

Best,
David.

[chakarov]

david.anastacio let me summarize what we found in our private messages so far , so it can be in help of other users.

* When V-ray is not installed or set in houdini.env, bake to texture tiles outputs black images. This is valid for H18+ , workaround for it is added and it is ON by default in debug tab "Force V-Ray env variables", still this fixes only when geometries are not loaded from external files. If you experience problems with installed V-Ray try to disable this toggle - it is still experimental

* Invalid normals (0,0,0) will be recalculated on export step of rendering, this is valid for "live" meshes only, not for alembics or V-Ray proxies.

* single points and curves causes also black output when baking, now those objects are disabled by default in V-Ray BakerTool, If you want to bake points or curves, first need to convert them in meshes.

* UDIM mask parameter is now available when bake to texture tiles is enabled, only udim indexes are supported for now.
syntax:
1001-1010 - this is how range is specified
1025 - specifies the exact UV tile
^ - for exclusion of the next exact tile or range of tiles
* - all tiles, from chosen range

you could specify include ranges / tiles as many as you wish and exclude as many ranges / exact tiles as you wish

excluded tiles are with priority over included ones. This means, if one tile is set as included and excluded, it will be respected as excluded one. This allows you to exclude a tile from a range or a smaller range from bigger one.

ranges/tiles should be separated by empty space, no comas or any other character.

always baking of texture tiles is evaluated in the range specified in UVmin and UVmax, UDIM mask includes/excludes tiles within that range only. If a specified range/tile does not exist in that range they wont affect the final output
examples:

* ^1020-1025 ^1035 - means every tile from the UV range above, excluding tiles 1020 1021 1022 1023 1024 1025 and 1035

^1015 1001-1020 - means every tile between 1001-1020 except 1015,

^1010-1020 * ^1035 1001-1040 – you could specify exclude tiles/ranges before the include ones or in any other messed order, of course in this example * includes last range in itself but it is still a valid mask

If status label shows a problem with udim mask, more info is available in debug console in debug tab.

[david.anastacio]

Hi chakarov,

Replying to the UDIM parameter that seemed to be missing. I just quickly lookd and I assumed the UV ranges were gone and were replaced by UDIM ranges. I should've payed more atention to you text

Thanks you.