Normals orientation on basic custom mesh

Questions
1

Hello,

I’m struggling with something simple, I’ve edited the playground of the doc about custom meshes to reverse the normal orientation, but I don’t understand why material isn’t displayed as I would expect

Playground link: https://www.babylonjs-playground.com/#VKBJN#233

I reversed all the normals

I would expect:

  • face (0, 1, 2 ) to be invisible when looking in the Z+ direction
  • face (3, 4, 5) to be white when looking in the Z+ direction

But I get the opposite.

Do I misunderstand backface and normals behaviour ? If we reverse the normal shouldn’t “back face” become “front face” ?

Thanks for any pointer on this

2

Hi, the front/backface are determined by the winding order of the vertices, so if you reverse the indices you get the desired result:
https://www.babylonjs-playground.com/#VKBJN#234

2 Likes
3

Ok !!! Got it :sunglasses: