Painted Vertex Colors damaged

I have one mesh in one level that has problems with painted vertex colors. Other meshes in this level or other levels works fine. If I paint the vertex color at one computer and open the scene on a different computer than the vertex colors are damaged. If I want to paint on this damaged mesh at the first click the whole mesh is filled with white.

Here are screenshots of the original and the damaged version:

Hi -

Somethings I would check right off the bat, look at the computer where the mesh looks corrupted and see if the Engine Scalability settings have been altered and if so return them to Epic and see if the mesh corrects itself. Also delete the Intermediate, Saved folders before you open the project on the second computer, this will force a shader recompile and hopefully remove any corrected temporary Shader Files.

Finally if none of those ideas work, can you let me know how you are viewing the vertex colors from the pictures above, is it directly from the Vertex Painting Preview or do you have a Vertex Color based Material applied to the mesh and if it is a Material can you post a screenshot of it? Finally and just to be thorough can you upload a copy of the DXDIAGs from each CPU?

Thank You

Eric Ketchum

Hi,
I’ve done some tests with 4 computers. Only one of them seems to make mistakes. If I paint at the “defect” computer, at all other computers the mesh painting is damaged like in the picture above (looks equal at these 3 computers). If I paint at one of the 3 computers then it looks correct at the 2 other “correct” computers but at the “defect” computer the mesh is painted full white.
I’ve deleted “Saved”, “Intermediate” and “DerivedDataCache” at the defect computer with no change.
The same failure now is at a different level with one mesh. It is the “Water” mesh again. But other meshes seems to be correct. Maybe the Mesh itself is incompatible with mesh painting in some cases? I’ll put the mesh in the Attachment:

link text

Hey -

So I tested your mesh and everything looks fine for vertex painting and it is rendering fine on the CPUs we have here. Are you working with any Macs? Can you let me know the DXDIAG for the bad CPU?

Thank You

Eric Ketchum

One of the “correct” computers is a mac. The DxDiag of the defect computer is in the attachment. It’s the only one of the computers with AMD CPU and GPU. Can this be the reason?
link text

Hey -

It is possible, but after looking at the DXDIAG, your card is a full version video driver behind, try to update the AMD drivers which you can do here:

http://support.amd.com/en-us/download

Let me know if this does not fix the issue -

Thank You

Eric Ketchum

Sorry for the late answer. The new driver doesn’t help. Is there something else I can look for?

Hi -

You provided the Water_Mesh in uasset format before can you upload a copy of the original FBX?

Thank You

Eric Ketchum

Hi,
in the past we had this problem only on one computer. We assumed that the graphics card was defect because sometimes it produces some graphics artefacts. But now we have the same problem with the mac that works before. In the Attachment you can find the FBX of one Water Mesh.

Sorry I cannot attach the file because its to big. Here you find a Link:
https://onedrive.live.com/redir?resid=9C958FCE66150B16!126362&authkey=!AKN-imNx-pvosXM&ithint=file%2CFBX

Maybe I’ve identified a relation to the poly count of the mesh. We have 6 levels with water meshes. 3 of them are incorrect:

Mesh 1: Tris: 8.560 Verts: 4.515 correct

Mesh 2: Tris: 33.872 Verts: 18.272 correct

Mesh 3: Tris: 45.696 Verts: 24.293 correct

Mesh 4: Tris: 25.152 Verts: 23.497 incorrect (with little bit different behavior: the mesh is not damaged with artefacts but it is full white)

Mesh 5: Tris: 41.172 Verts: 42.737 incorrect

Mesh 6: Tris: 101.112 Verts: 157.419 incorrect

I hope this helps.

Hi user37337 -

I am still unable to reproduce the issue on your asset from above. I am getting expected results in 4.7.6 and in 4.8.2.

For Testing I used a Standard Opaque Material set to unlit and a vertex Color node input into Emissive Color. I checked your normals in Maya and everything looks correct in the FBX. Can you think of anything else that you are doing with the meshes that are incorrectly rendering that you have not mentioned. I know it is a simple material but can you post a screenshot of it just for reference.

Thank You

Eric Ketchum

As a workaround we splitted all water meshes to parts of 10000 to 15000 triangles and repainted all. Now it works. (Also this is better for performance…)

Edit: our Water Material is complex. What you see in the screenshots above is the vertex painting mode. But in the Material we’ve seen the same artefacts.

Hi -

Without seeing your full material setup, I can only wager a guess as to the root cause, but even in vertex painter mode, the engine will attempt to show what the material is doing in the vertex shader on the applied mesh. Do you get the same errors on a large mesh using a material that is Opaque Unlit with just Vertex Color plugged into the Emissive Channel? If you do not get the error, then it probably is something that is happening in your material in the vertex shader components, like WPO or Custom UV settings.

Thank You and let me know -

Eric Ketchum

i have the same problem here!

Hi Grafix -

Do you have a mesh asset and material asset(s) that you can share for us to attempt to debug further? If you have a sample project as well feel free to link or attach the whole project as well.

Thank You

Eric Ketchum

Here´s the mesh where the vertex colors don´t want like i want

Hi Grafix -

Can you check your FBX, I can neither open it in Max 2015, Maya 2014 or in the Editor?

Thank You

Eric Ketchum

it is an maya 2016 fbx but i can export it again

link text