Is there a way to display face normals?

Hey folks,

I know we have a way to display vertex normals. But is there a way to display face normals as well?


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Try using a flatshaded mesh. See example here:

The second box is not using shared vertices so it should give you the vector you are after.

@Michael_Prosser thank you for the response!

But in this way, its actually still displaying the vertex normals?

Just wondering in general what’s the relationship between face normals and vertex normals?

Is face normals get calculated first by a cross product on edges, then → vertex normal?
Or the other way around?

Or these 2 things are calculated independently?

Sorry totally new to lower level computer graphics here. Asking these 101 questions…

I could be wrong but I think the face normal is the direction of face where vertex normal is direction of vertex data - if flat shaded though, The vertex normal should point in the same direction as face itself.


gotcha. Is it possible face normals and vertex normals are pointing to different directions?

If they are shared normals they will be different from face. If you look at that link - the top box is shared normals, The bottom is flatshaded normals - these do not point in same direction. The bottom box points the same direction as the face so this should be the same value as a face normal.

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you could always check this as well

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And here in this example you will see they are the same:

but the position of marker in center of each facet here.

@Michael_Prosser Oh that’s it!! Thank you so much!!!

I missed this entire doc section when I was searching. I was trying to search “face” normals with babylonjs and didn’t realize the term “facet” is actually what I was looking for. :grimacing: :smile:

Maybe will it be better putting display vertex normal doc page and that display facet normal page together in the docs? Now these 2 pages are at different places.

All things make sense now.
Many thanks again.