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I created a cylinder which I remeshed and sculpted some details on one of its sides, when I apply transformations or try to join this of object with another object it gets distorted and sort of inverted. Hoping someone could help with explaining why this happens? Please see video for further info.

https://youtu.be/hmPOj0qCvMA

file:

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  • $\begingroup$ could you please share the object? blend-exchange.com $\endgroup$
    – moonboots
    Jan 31, 2023 at 10:36
  • $\begingroup$ Yes, I have added it to my post, thank you in regards. $\endgroup$ Jan 31, 2023 at 11:41

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You probably have Backface Culling enabled

backface culling

and your object is scaled to -1 on one or all three axes (two axes won't be a problem): this makes it look like you don't have inverted normals, they look correct but only because the scale is inverted.

inverted scale

If you now apply all transforms, the scale will be reset to 1. In this case it means, the normals get flipped because other than the mesh vertices which simply stay in place, normals have a front and back and inverting the scale makes a difference on them. And with backface culling enabled, the front faces are now invisible and show the rear faces, which are blue because they are pointing inwards.

reset scale

If you would disable backface culling it will become obvious, because now the front faces are shown in red.

flipped red faces

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  • $\begingroup$ Thank you for your answer. It appears as though the scale is inverted but on only the z axis, however you are correct when saying that I have backface culling activated and that when I deactivate that and apply all transformations, the faces appears red or flipped. So I just have to flip them again and everything is fine. Again, thank you for your answer! $\endgroup$ Jan 31, 2023 at 11:50
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    $\begingroup$ @RenderGenderBlender Only on the Z axis, well yes as I said - on one or all three axes. If it were two axes this wouldn't happen, it's the old mathematical rule of minus times minus gives plus. Only if you have an odd number of inverted scales it will flip the normals after applying - so, contrary to how I phrase it in the answer, your normals were probably correct in the first place, they get inverted by the scale resetting. Is this helped you, would you consider accepting the answer? What should I do when someone answers my question? $\endgroup$ Jan 31, 2023 at 12:09
  • $\begingroup$ Yes, now I can see you wrote that! Very much a help, thank you again! $\endgroup$ Jan 31, 2023 at 12:40
  • $\begingroup$ If the answer is correct, validate it ;) @RenderGenderBlender $\endgroup$
    – moonboots
    Jan 31, 2023 at 13:07
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    $\begingroup$ @RenderGenderBlender If someone found a solution to your question, you can accept it by clicking on the checkmark to the top left of the answer. This also shows other users that might have a similar problem that there is a possible solution to it. It also shows people who are trying to help that there is not necessarily a need for another answer. Read more about it here: What should I do when someone answers my question?. Generally the Help Center here is a good resource on how this place works. $\endgroup$ Feb 17, 2023 at 11:09

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