Skip to main content
Question

Behaviour of mesh and appearance

  • August 13, 2024
  • 1 reply
  • 69 views

takanaka
Contributor
Forum|alt.badge.img+5

Hi,

 

Can someone explain the following behaviour?

Goal: create one mesh with each surface as a ‘flat’ color’ without shading. 

Problem: I get a shading effect that I do not want after merging many faces into one mesh.

 

Images are attached. The first image is correct, it shows each side as one flat shading of the color #c8c8c8 (200, 200, 200). This is when I applied that as appearance to each single part (40.000). After merging all these 40.000 Faces or Meshes into 1 mesh, a new shading is applied that is undesired. I use MeshMerger with default settings. Can someone explain to me why this is happening and how I can prevent this to happen? If I re-apply the appearance to the single mesh it still gets the shading. Why is this happening? Where is it coming from?

 

I also tried using appearance from a single jpg with the solid color, but this also did not work. 

 

Thanks.

1 reply

takanaka
Contributor
Forum|alt.badge.img+5
  • Author
  • Contributor
  • August 14, 2024

OK so now I figured out it is the surface normals. If I remove them, it breaks the appearance of a dataset that is looking correctly. If I have correct surface normals on a collection of faces, and aggregate them or mesh them and MeshMerger them, why does it remove those normals? How do I set them back? I see in FME 2024 a VertexNormalGenerator, but I am stuck on 2023. 

I know the correct normals (I can extract them before merging) but is it possible to place them back afterwards?