Hi guys, sometimes I import models into babylon, which have wrong normals (for example they are “black” when light is turned on). Is it possible to detect, when they are wrong and need to be flipped? P.S.: I’m using a right handed system. Best regards, MrGroove

I’m looking for an algorithmic way. Possibly detect the side orientation?

I’m not an expert on computational geometry, but as far as I know there’s no “perfect” solutions for the general case, only approximations and heuristics. If you can make some assumptions about the geometry then there might be a way; I’ve implemented one approach for terrain that could only consist …

Hi @MrGroove just checking in, was your question answered? :smiley:

@MrGroove : I have been dealing with this issue both with importing into BJS and exporting from BJS. I have had success with fixing up the normals in Fusion 360 before importing. There is an option to repair imported meshes by “wrapping” them. I have also tried doing the same with algorithms and h…

Hi. I also have the same problem. I need a way to detect if the imported asset is based on left or right handed system. Thanks.

What format are your assets in? If you aren’t using a format with a defined handedness (like GLTF, which is always right-handed), this is a difficult task :slight_smile:

How do I interpret the colors? Or rather: what color or coloring indicates that something is wrong? Also, if vertex normals are rendered as expected, will this be sufficient to tell that normals are correct?

Hi, The subject is kind of complex and complex to achieve with just the tools of the inspector. In essence, the colors of displaying normals from the inspector can help you detect if there’s something wrong with your normals/normals interpolation but they won’t tell you the source of the issue. Ver…

Thanks @mawa for the great explanation :slight_smile: And I have to say, holy shit, was totally not aware of the complexity normals have. Your second paragraph makes me actually worried because, well, it is a bit like that Futurama episode where they eat these super tasty snack thingies that turn ou…

Detect if normals are "correct" or need to be flipped?

Questions

mawa May 12, 2022, 1:25pm 2

Hi,
I suppose you know about the ‘inspector’ debug section? ‘Display Normal’ and ‘Render Vertex Normals’ debugging options on mesh selection should help with that. I guess.

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Detect if normals are "correct" or need to be flipped?

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