When objects created with mirror transformers on Blender, the normal faces bug on Substance Painter

[David29389086hh8u]

I hope you can help me, I will try to be as precise as possible.

The problem is on the right leg and the right leg of my Robot, the basic modelling is the left leg and the left arm of the robot, when I finished modelling the left arm and the left leg, I copied and pasted them, then I applied the mirror transformation (Object>Mirror>Y Global) to create the right arm and the right leg.

This is where the problem starts, the faces are also inverted, so I select the right leg and the right arm > "alt+n">"Flip" so that all the faces of my model appear in blue (the right way for Blender).

I export my model in .fbx format, and open it in Substance Painter, the right arm and leg have the faces reversed, while all the faces in Blender appear in blue to indicate the correct direction of the faces.

I try to re-flip the right arm and leg, they appear in red on Blender > I export again in .fbx > open on Substance, and surprise ! the faces appear in the right direction, while on Blender the faces were in red.

I start to Baker the model to be able to work on the texturing of my model, Baker finished, I put a Smart material, but on the right arm and the right leg, I have the impression that the texture appears in the bad direction, whereas on the left arm and the left leg, the texture functions perfectly.

The ambient occlusion is done in the wrong direction, that's probably what puts the texture in the wrong direction...

How can I fix the problem ????

Translated with www.DeepL.com/Translator (free version)

[Cyril Dellenbach]

Hi David,

Thanks for the message.

I'd advise you to always export your model with the correct normal orientation (blue faces for Blender), even if there is an issue with Substance 3D Painter. I'd also advise you to make sure you apply All Transforms (Ctrl+A > All Tranforms) before exporting your mesh. 

With that being said, the problem could come from something else. Have you checked there is no issue with your UVs? Any of them are overlapping?

If the issue persists, would you mind sharing your meshes? You can send it to me privately if don't wish to share it here.

Keep me updated.

[David29389086hh8u]

Hi Cyril,

Thanks for the response, all UVs are corretly placed, no one of them are overlapping.

Im ok to share with you in MP my Blender project, if it makes it easier to find the problem.

Thank you, see you in private message.

[Cyril Dellenbach · Accepted solution]

I'm posting here the answer for anyone who might have the same issue. 

Before exporting any model from Blender (or another modeling software), it's usually good to Apply all transforms to make sure every transformations made to the model is transferred to the object data.

Once the transformation is applied, you can check there is no issue with your normals before exporting.

Best regards,