Unexplained Red Reflection/Overlay on Model

Hi Everyone,

So I made a very simple haunted house model in Blender and stuck it into my scene. As soon as I add any light source to the scene the house becomes blood red, but you can still see the underlying textures so it’s a bit of a transparent effect. If I remove the light the house looks normal again. I’ve not yet been able to fix it by adjusting settings in Blender and I’ve not been able to fix it by playing with “setColor” on either the model or the light. I thought it might be some kind of emission or reflective property that I somehow put into my model’s materials but I’ve set everything I can find to 0 inside of the Blender properties. Does anyone know what might be adding this red effect to my model?

My script is as basic as it can get. I setup the window and camera, add one directional light node using default settings, load the house’s model, and then place it down at 0,0,0.


Does your model perhaps have vertex colours? That might account for the red tint.

Otherwise, are you perhaps calling “setColorScale” somewhere in your code? (Even if not on the model itself.)

Thanks for the quick reply.

I don’t think it’s the vertex colors as I have gone into the object properties and removed “Col” from the Vertex Colors section and it still has the red effect in Panda. Is there anywhere else that I would need to go in Blender to make sure it does not have any vertex colors being added? I’m pretty new to Blender so I’m trying to look online for some explanations as well but they all point me to that location in the object properties.

And I’m not calling “setColorScale” anywhere in the code. Everything is default on the model and lighting other than the position that I’m placing them in. It’s just calling them in and dropping them into the scene as-is.

Oh, one more idea, if a long shot: I don’t suppose that you’re unintentionally setting your light-colour to be red, are you?

And another thought: what happens when you view your object in PView? Specifically, what happens when you view it in PView and activate lighting (by pressing “L”), and perhaps activate per-pixel shading (by pressing “P”)? Do you still see the red tint there?

That said, what version of Blender are you using? If it’s 2.78c or earlier, you could perhaps put together a small demonstrative blend-file that shows the problem on your end, and I could take a look at it and see whether there’s anything obvious that might cause the problem.

If it’s a later version, my version likely won’t be able to accurately open the file (as I use 2.78c)–but perhaps post it anyway, in case someone else uses a version that can.

[edit] Or for that matter, perhaps put together a small test-model–just a cube–that demonstrates the problem on your end, and then post the exported version of that model. I can perhaps take a look at it in Panda.

My light color is using the default settings, and strangely enough I believe that direct light is actually removing the red tint a bit. If I move the light closer the red tint fades more.

I looked at it in PView and “L” does make the red tint show up and then if I push “P” after “L” it seems to change the red tint a little but it still remains there.

I’m using the latest version of Blender. I just attached a blend file that has a simple box in it that’s affected by the red tint. Hopefully it will open for you.

Box.blend (828.9 KB)

Okay, the red tint appearing in PView somewhat rules out the problem being in your program, I think.

Unfortunately, as I expected, the blend file doesn’t open properly in my version of Blender.

Given that, I do think that posting an exported version of that “box” blend-file (i.e. either an egg-file or a bam-file) might be the easiest way for me to examine what’s going on.

(Presuming that no-one else comes in either with further ideas or a version of Blender that does open the above, and that you don’t find the problem yourself.)

Here’s an exported version of the box in the egg format.Box.egg (9.6 KB)

The problem is in the material.

<Material> Walls {
  <Scalar> baser { 1 }
  <Scalar> baseg { 1 }
  <Scalar> baseb { 1 }
  <Scalar> emitr { 4 }
  <Scalar> emitg { 0 }
  <Scalar> emitb { 0 }
  <Scalar> emita { 0 }
  <Scalar> shininess { 0 }
  <Scalar> roughness { 0 }
  <Scalar> metallic { 0 }
  <Scalar> ior { 0 }
  <Scalar> local { 0 }

<Scalar> emitr { 4 }
Replace with 0
<Scalar> emitr { 0 }

Which exporter do you use?

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Ah, I’m using the renewed YABEE exporter for Blender 2.8. Can you tell me how I can get to those properties within Blender? I’m looking at the material section now and I don’t see anything related to “emitr”. If that is referring to the red value of the Emission property then it’s already been set to 0 on the material so I’m not sure what’s going on.

There isn’t really an official updated YABEE as far as I know. So this question can be asked to the author of the modification.

It is recommended by the developers of the plugin for exporting from blender at the moment.

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Thanks. I’ll look into it and see if it exports things correctly.

The unofficial YABEE fork exports everything with a red emission colour. Apparently it’s written to be used with the RenderPipeline, which interprets this red emission colour in some special way. I don’t recommend using it.

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Added RP Compat option which now activates RP-specific material parameters like emission colors, defaults to False. This means 3D models now look correctly with native Panda3D renderer and SimplePBR