Alembic GEO and texture map coords issues

Howdy, I have an object with multiple materials brought in through the Alembic importer. Of course, I have the issue of textures being flipped, as I believe was pointed out in another post, but I am having further problems where the UVS don’t seem to be respected at all.

You can see the red arrows pointing to 3 different materials, each what should be showing the UV alignment texture in it’s entirety. Instead it is using the coordinates of the first material, which covers most of the object

Also, the GEOMETRY SEEMS FLIPPED

When you look at the image below, from 3DS Max, you will notice that the two smaller material/textures are on the top, but when everything is loaded into UE4, they are on the bottom

Hey SterlingY,

So in order to assist I will need the assets your are using and an outline of the process you are following so I can reproduce the issue on our end.

Also, the GEOMETRY SEEMS FLIPPED

This is a known and reported issue which you can track by following the link below to our Public Issues Tracker.

UE-35510

I believe what you are seeing is just a side effect of the importer flipping the axis and causing your UV’s to appear offset. I could be wrong though, so if you could provide me with your mesh to test with, I can investigate further.

Thanks,

Andrew Hurley

Attached is a link to the MAX file. There seems to be a bug on the MAX side of things but I don’t think this has anything to do with the problem stated above:

The frames you are interested are 35-111

  1. From Max, Export Alembic
  2. Set range to 0 - 111 (if you export 35-111, it exports 0-76)
  3. In UE4, Import File
  4. Choose Cache Mode
  5. Set range 36-112

So myself and another colleague opened up your Max file and discovered a number of issues with your mesh, which are more than likely the culprit of your issue.

Firstly, you have multiple material ID’s (9 to be exact) which are not all assigned a material. You want to make sure that however many material ID’s you are using, that you have assigned a material to the respective ID’s.

Another issue we observed, was that you had quite a lot of modifiers in your stack, which can cause a lot of issues when it comes to exporting. As soon as you export, all the stacks are collapsed and the UV’s and other modifiers can be wrong.

If you can reproduce this issue using simple primitives, like a cube, and a few materials with a simple animation, then we can investigate further. Let me know if you have further questions or need additional assistance.

Cheers,

Andrew Hurley

The Max mesh is a work-in-progress, which is why the 9 materials were not all in place. I just put a few on there for testing purposes. Yes, there are a lot of modifiers because it was a cloth sim and then modified to give it thickness and so forth. You can’t collapse the modifier stack because then it loses its vertex animation.

No worries, I was simply trying to point you in the right direction as well as get a minimal test case so we can confirm this is a bug within the engine. Let me know when you have a simplified test case that can reproduce the issue and we can continue forward with the bug reporting process.

Thank you,

Andrew Hurley

Hi Andrew, I apologise if I’m replying in the wrong post, but too suffering from UV issues and had a Blender dev up in arms about UV issue and would appreciate any assistance from an UE4 developer. This is my try in Blender to UE4… Please also find attached a .Blend file with a basic texture as used in the UE4 screen below…

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Hello Andreve,

I was able to confirm what you are reporting and have gone ahead and entered a bug report for the issue. You can track the issue following the link below on our new Public Issues Tracker.

UE-36190

Once the issue has been addressed by our engineers, the fix will be added to the release notes for fixed issues within an upcoming full engine or hotfix release.

Let me know if you have further questions or need additional assistance.

Cheers,

Andrew Hurley

Thank you Andrew, I’m very excited!