Blender Some (flat) meshes in Blender display weird colors

[deHavilland]

Do these pictures trigger anything you already encountered?

Usually when I create a new material and activate the MSFS extensions by changing the type from 'disabled' to 'standard', the mesh turns to white ─ until I fill the base color texture slot.
But now I have a few meshes that turn to weird colors. And they stay like this, even when I bind a texture (though I may see the texture 'underneath'). And btw, after exporting the colors show up in 3D viewer as well as in MSF2024 SDK.
I must mention all meshes 'affected' are 2-dimensional sails/planes. But I have lots of experience with fabrics (and use them 2-sided). The normals look good, one side blue, the other red.
Using Blender 4.2 with Exporter 4.3.5 (also tried other Blender builds and Exporter 4.3.3).
Any insights appreciated!

 

[ronh]

you may have inadvertently add Vertex colors to your meshes.


the Color attribute causes this if it is not all white - I think

 

[deHavilland]

Thanks ronh, and though I don't think I have any inadvertently activated vertex colors, it encouraged me for some more testing. And I did the strictly forbidden: I manipulated the MSFS standard graph. In the end I found a potential culprit: the base color group. When I bypass it, the material looks like intended. But then I can't really imagine why that node should do something like that. And I really don't want to risk such unsupported manipulation. Do you see a way out?

 

[ronh]

if you open that group node you will see that there is a vertex color node in there. so I assume that some vertex color is making that.

See the "color" attribute. you can't just delete (at least I don't know how to simply fix them) - you need to make those vertex colors white

Each mesh may have one or more.

Also your pic shows missing node connections. - should look like this.

What some don't understand is that these nodes are just there to "show" you how it "may" look in the sim. The render engine in blender is being manipulated by those nodes. The exporter uses those nodes, plus additional msfs_* variables to export the gltf.

with a vertex color of blue add and the vertex color node directly into the base color there is a blue corner

Reconnecting things back I get a texture plus the blue vertex.

vertex paint mode

 

[rhumbaflappy]

I think those are vertex colors as Ron suggested. To view vertex colors in Blender:

 

[deHavilland]

Thanks much Ronh and rhumbaflappy, your answers were most helpful to me. I must confess, I hadn't even known that the graph nodes were like Mandelbrots where I could zoom in and open them. Nor had my workflow ever required to go into Paint mode ─ but seems an interesting way of manipulating materials 'on the spot'!
Btw, I had stripped the original FS24 material graph temporarily for debugging.
Anyway, with the help of a huge paint radius and max strength 10 I finally managed to remove/overpaint the rainbow colors! However I found it a bit odd to repaint every LOD and turn the mesh around so that I'd get all faces.This time I asked Claude.ai and got that nicely working hint:
Option 2 - Set Color Attribute to neutral:
1. Activate Vertex Paint Mode
2. Select the problematic Color Attribute (dropdown on the right)
3. Paint → Set Vertex Colors → Choose White (1,1,1,1)
4. This sets everything to neutral white

 

[rhumbaflappy]

Here's a Blender addon (I tested with version 3.6) that will set all of the selected objects to a white vertex color. I used Microsoft CoPilot to sort out the code. Used in Object mode:

 

[deHavilland]

Works like charm (I use 4.2), rhumbaflappy! All meshes in all 5 LODs in the blink of an eye. You (the Captain) and copilot are geniuses! I wonder what you mean by 'sort out the code' and if you'd reveal what you prompted for?

 

[rhumbaflappy]

I asked CoPilot:
Can you make me a blender addon that will set all the color attributes of a selected object to white

I didn't like the solution because it only worked on one object selected, and I had to adjust it a bit as it had an array of 3 colors, when it needed 4... Blender pointed this out as an error, and I corrected the code. I then asked:
Could you make this to set all selected objects to a white vertex color?

That did the trick. I saved the code as VertexColors2White.py, and zipped it for a quick addon. I like using CoPilot. It just sits there on my taskbar waiting for me to expose my ignorance to it.